Family Relationship Switcheroo was renamed from "Are You My Mummy" in order to clarify the meaning of the trope that would otherwise be difficult to figure out if one was not familiar with the Doctor Who reference in its first name.
Family Rivalry was renamed from "Family Feud" because the original name was also the name of a TV series, and literally all incoming links were in reference to the TV series.
Fang Thpeak was originally titled "Whedon'th Thyndrome", which was changed after it was noted that Joss Whedon didn't really have anything to do with what it was about.
Fan-Preferred Couple used to be called "Better than Canon", and was "Sasami Syndrome" (after Tenchi Muyo!) before that. The reason for renaming from Sasami Syndrome is because it was advocating a specific opinion that a lot of people just didn't agree with (plus had some incest/pedophilia Squick to it in some continuities), while the rename from Better Than Canon was because it was both suggesting fault in the creators while also sounding vague enough to just be any fan talking about how they can supposedly make something better (which is what the current page is about).
Faux Symbolism used to be called "What Do You Mean It's Not Symbolic?", which caused problems with being easily interpreted as the opposite of the actual trope and fueling mere complaining about symbolism you don't like.
Favouritism Flip Flop was formerly "Appeal to Libido". The fact that it's hard to tell that the two names were even for the same trope is a big part of the change reason.
Fear of Thunder was formerly known as "Thundraphobia", which is a portmanteau but not a real word. (The actual phobia is "Tonitrophobia", but who could ever remember that?)
Featureless Protagonist was "AFGNCAAP". It was renamed because the old name was an impenetrable and hard-to-remember acronym.
Feed It a Bomb was renamed from "Dodongo Dislikes Smoke" from being work/fandom dependent and being misleading.
Felony Misdemeanor was once "What Do You Mean, It's Not Heinous?", renamed for being an ambiguous snowclone.
Fiction as Cover-Up was originally "Masquerainment", an opaque portmanteau of "masquerade" and "entertainment". A name like this is impossible to search for, and as a result it saw severe underuse.
First-Person Peripheral Narrator was renamed from "The Ishmael", because of confusion about exactly what the trope meant, misuse, and because there are many notable characters named Ishmael that have nothing at all to do with the trope described.
Foreign Wrestling Heel was renamed from "Evil Foreigner", because at had well over 20% misuse for any villian of any type that happened to be foreign to the protagnists, foreign to the makers of the story, or foreign to the troper writing the example.
Full-Circle Revolution was once "The Thermidor", probably as a reference to some aspects of the French revolutionary government's behavior once in power. Not helped by the Thermidorian Reaction being the most common meaning of The Thermidor — something which was the opposite of the trope.
Future Food Is Artificial was known as "Soylent Soy", a muddled snowclone of Soylent Green. The "soy" part was redundant and the cannibalism connotations were just misleading.
Gambit Index was originally "Xanatos Planned This Index". The name was changed because not everyone knows Gargoyles, where the character Xanatos hails from. In addition, several tropes under Gambit Index used to have Xanatos in their names as well, and tropers are concerned that an excessive number of Xanatos-named tropes can lead to the Trope Decay of Xanatos Gambit by overuse of the Xanatos meme causing it to become a byword for Evil Plan or a generic The Plan rather than a distinct trope of its own.
Gambit Pileup was originally "Thirty Xanatos Pileup". That was renamed because Gambit Pileup doesn't have to include gambits of which lead to success no matter what the other person tries.
Gambit Roulette was "Xanatos Roulette", and before that it was "Yagami Gambit".
Spanner in the Works was formerly "Xanatos Gilligan", changed for being for being rather impenetrable without considerable prior knowledge of the site and being vague with it.
Gameplay Roulette was originally called "Genre Roulette". Renamed because the use of Genre made it sound much broader than was intended; it's a trope specifically about gameplay styles in video games, but the title gave no indication that it's specifically about video games, or that meaning of "genre".
Global Currency Exception was formerly "Your Money Is No Good Here". It was renamed because it sounded like a stock-phrase and caused confusion over whether the trope was medium-specific.
Glorious Mother Russia was originally "In Soviet Russia Trope Mocks You". Usage just to make Yakov Smirnoff jokes led to them being separated, the former to fictional portrayals of Russia, the latter for the original joke.
...and The Gods Must Be Lazy was formerly titled "God's Hands Are Tied". Two separate articles, whose titles were switched because they'd somehow originally been titled backwards. Apparently, the article now known as God's Hands Are Tied was written first, and was given a punny title rather than a thoroughly accurate one. And then whoever wrote the article now known as The Gods Must Be Lazy was simply unaware of the other article's existence.
The Golden Age of Comic Books was formerly known as "Golden Age". It was renamed because not only are there golden ages for other media, but there were also references to the concept of a Golden Age independent of comic books.
Go Look at the Distraction was formerly known as "Crummies", after a phrase which induced this reaction in an episode of Friends. Renamed for being thoroughly unintuitive.
Gratuitous Disco Sequence was initially launched as "Everything's Funkier with Disco"; it was renamed as part of the general effort to get rid of "Everything's Better with" snowclones.
Gratuitous Iambic Pentameter was "Pardon Me, Stewardess, I Speak Iambic Pentameter". The old name was too long and an unnecessary Shout-Out to Airplane!, which doesn't even have any examples of the trope (though it does have its "Pardon me, I speak Jive" moment).
Great Gazoo was originally "The Ozmodiar", renamed because Ozmodiar was a one-shot joke Gazoo ripoff.
Green-Eyed Epiphany was once "Skater Boy Syndrome" since the trope appears in a Avril Lavigne song. It gave no information to non-fans and the song isn't a typical example, with a nonstandard viewpoint and outcome. The new title features jealousy and realisation.
Hair-Trigger Temper was once "The Pesci" after the actor Joe Pesci who famously played characters with Hair Trigger Tempers in Goodfellas and Casino. In both cases, there were maiming and death that isn't essential to the trope. Those who didn't get the reference or got the wrong reference from one of his other roles weren't informed as to the nature of the trope.
Happy Ending Override was previously named "What Were We Fighting For?", but was renamed for being non-indicative and leading to misuse about people with unclear goals. What Were We Fighting For? is now a redirect to Was It Really Worth It?.
Hard-Drinking Party Girl was known as "Bottle Fairy" but was changed due to the name being unclear and could be easily confused for a literal bottled fairy or the anime, Bottle Fairy. The trope was also getting misuse for any girl (and even a few guys) that drank or partied regardless rather it actually fit the trope's description.
High School Hustler was once "Parker Lewis Ferris Bueller". It was renamed since the old title was too long, depended on people getting the references, didn't have as much immediate meaning, and didn't work as well in a sentence. In part, it replaces potholes redirecting "high school hustler" to the old title.
Honest John's Dealership was formerly a subtrope of "CMOT Dibbler" (named for a character from Discworld). Dibbler was put up for rename because it's unintuitive for anyone who hasn't read Discworld. The rename discussion led to both tropes being merged under the Honest John name.
Honesty Is the Best Policy was once "Washington Gambit" after the story of George Washington and the cherry tree. Washington was known for many things, honesty being only one: this gambit could have been a wartime strategy. Others thought it referred to federal politics, and honesty isn't the first association.
Hot-Blooded Sideburns was "Go Nagai Sideburns". It was renamed, because not everybody knows what a Go Nagai is (The creator who popularized this trope).
Hot Paint Job used to be "Everything's Hotter with Flames". Renamed since the previous title wasn't specific enough, plus it was named according to the discredited and unrelated "Everything's Better With X" snowclone family.
Hub City was "Capital City" but was renamed for having nothing to do with capitals. Which in turn was originally named "Shattrath City", after an Outlands city in World of Warcraft.
Hub Level was previously "The Hub", but was renamed in order to not conflict with Hasbro's The Hub, a TV network.
Humans Are White used to be "Least Common Skin Tone", but was renamed because the original title was a snowclone that was unclear and led to misuse of the trope outside of its specific definition of people who are white being dominant for no real reason in futuristic, fantasy, and alternate universe settings.
Ignored Aesop was formerly "Aesop Ju Jitsu". Renamed for being opaque.
Ignored Expert was renamed from "The Jor-El" to clarify the trope and because the former name was a work-specific and character-named trope title.
Ignore The Disability was "Sammy's Glass Eye", after a scene in All in the Family. Sammy, for Sammy Davis, Jr. has no relevance, it's all in the glass eye. But that still didn't convey the idea that it is trying to leave someone's disabilitynote or a similarly taboo topic related to a personal attribute, such as a very large nose out of a conversation (then making an embarrassing slip.)
I Let Gwen Stacy Die once simply was "The Gwen Stacy". Changed because a) it's a character name and b) the trope, as the current name says, is about letting her die, not about the living Gwen Stacy.
I'm a Humanitarian used to be "Soylent Green Is People". This may confuse people who don't get the former joke.
Impossible Hourglass Figure was originally "Hourglass Hottie". Renamed because the old name led to misuse for any woman with an hourglass figure.
Imposter Forgot One Detail was renamed from "Imposter Jamie Has No Accent" to avoid using a name that was work-specific and to help encourage uses of the trope that feature more than just accents. And the idea of a person with no accent is fairly ridiculous.
Improbably Female Cast was "Pink Bishōjo Ghetto" for a very long time. Anyone who didn't know what the word "bishōjo" meant wouldn't understand the title. On top of that, it was a poor snowclone of the term "pink ghetto", which aside from being a fairly obscure term to begin with, the actual definition of "pink ghetto" is the opposite of what the trope is about.
Improperly Placed Firearms was renamed from "I Know That Gun" in order to clarify the trope's meaning and decrease misuse for trivia and examples of prop guns being based on real guns.
Inaction Sequence was formerly known as "Not So Fast", but it was easy to confuse with the mostly unrelated "Not So Fast Bucko" (which has itself since been merged with Your Princess Is in Another Castle). Spent some time as Midstrike Monologue in between.
I Need to Go Iron My Dog used to be "Helicopter Sounds" after a Friends scene. It was changed because the trope has nothing to do with helicopters nor sounds and the Friends reference itself didn't quite fit.
Inept Talent Show Contestant started as "Pif Paf Pof", but the title was an obscure reference with little relation to the trope and the page wasn't thriving.
Inexplicably Awesome was "The Frizzle". It was renamed due to being a character-named trope whose name was causing a great deal of confusion over what it actually meant.
Inexplicably Identical Individuals was originally "Nurse Jenny". Renamed due to its obscurity to anyone outside of the fandom (especially since it was actually a portmanteau of two different characters) and the misleading link to the various Nurse tropes.
Infinite 1-Ups was "One Up Sampo". There was slim to zero chance the reader would know that one of the many, many meanings of the word "sampo" in ancient Finnish mythology is "mill".
Instant-Win Condition used to be "The Enemy Gate Is Down", after the quote from Ender’s Game. Renamed because it doesn't necessarily relate to enemies, gates, or gates being down. Also, "down" referred to the direction, not "going down".
I Read It for the Articles used to be known as "I Watch It for the Economics", at least partly based off a online meme that arose from the anime Spice and Wolf. The original name was not general enough to describe the trope, though, hence the change. It helps that the current name is also a meme, but one much older and more widespread.
It Gets Better used to be "Get on with It Already". Renamed because the original name is solely indicative of pacing problems, and not the specific type of pacing problem the trope is about.
It's Been Done used to be known as "The Simpsons Did It", named after an episode of South Park which deals with this trope. It was renamed because the trope seemed to be affiliated with The Simpsons exclusively.
Jaded Washout was "Al Bundy", but it was renamed because Al Bundy is known for more than just what the trope is about and how Al Bundy may be unfamiliar to many people.
Japanese School Club used to be "Club President", even though the trope was almost entirely about the clubs themselves and not the president in particular.
Journal Roleplay was "Livejournal Roleplay": while this style did start there, most of it's on other sites as of 2012.
Just Train Wrong was "Did Not Choo the Research": "Choo" wasn't clearly evoking trains for all readers (not to mention that it just sounded dumb). The replacement title has "train" and "wrong": errors depicting trains.
Knuckle Cracking was renamed from "Cracking Up" in order to discourage misuse for the other meanings of Cracking Up and to clarify the trope.
Kudzu Plot used to be separate from "Claremont Coefficient", named for X-Men writer Chris Claremont, who left so many plot threads dangling, for so long, that many had to be resolved by other writers after he left.