These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Badass Decay: Freddy never joined the good guys (who would want him?) and always was a serious threat to them, but as the series went on, he became quite the jokester, and became goofier and more playful with people's dream sequences than he was in the first few films. This came to a head in Freddy's Dead, where he turned someone's dream into a Nintendo game, where you can tell he's having a great time.
Believe it or not, Freddy has an extraordinarily high amount of fangirls. The fandom likes to portray him as a woobie whose terrible past and upbringing were responsible for his psychosis, and that his love for his daughter was genuine enough to push him off the deep end when she was taken away from him. The fact that Robert Englund has said on multiple occasions that Freddy represents neglect doesn't help this image either.
Misaimed Fandom: It is truly disturbing how many 12 year old girls on deviantART draw cutesy anime-esue fan art about Freddy Krueger falling in love with their Distaff Counterpart OC of him they made. Who knew skinless demonically powered child rapists are so "cute"?
Moral Event Horizon: Freddy Krueger crosses the line when he murders his own wife for discovering he was the Springwood Slasher.
Nausea Fuel: Freddy just loves invoking this, in the most ghoulishly creative of ways.
The whole concept becomes significantly less scary when you remember that Freddy only kills in one suburb (a fictional one at that), though it does get worse in Freddy's Dead, in which he states that "every town has an Elm Street" and makes clear that he's planning to expand his reach to the whole world.
As the original series goes on, Freddy's burned skin goes from horrfying to looking like a mild skin condition.
Physical combat isn't Freddy's forte, as whenever he tries to go up-close-and-personal with his victims, he loses. Freddy vs. Jasonaverts this by making him able to have an even fight with Jason.
Paranoia Fuel: The premise alone qualifies, obviously. It's one thing when you fall off a cliff in your dreams and wake up safe at home seconds later. But it's completely different when that can cross over into the real world.
Sequelitis: Outside of primarily Dream Warriors and New Nightmare, every one of the sequels receives a sizeable amount of dislike.
Villain Sue: From about the third film onwards, Freddy was pretty much undefeatable except when he chose to be. It got to a point where audiences met Freddy's Dead: The Final Nightmare with total cynicism (note how hard the title has to work to establish that he's really going to die in this movie).
Alice Johnson. Has all her friends and her brother killed by Freddy the first time out. Convinced she had him beat, he instead comes back and kills her boyfriend/father of her child, then he sets his sights on corrupting and possessing her unborn child? Life is not good to her. What's worse, all those deaths happen as an indirect result of her own dream power.