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.
The same can also be said for Sara McEveredy and Clan Wolverine. Innocent victims of Nicholas' manipulations, a powder-keg waiting to go off or power-hungry monsters who merely were caught out before they could act?
Hanse Davion and Katrina Steiner are awesome leaders if you lived in the states that became the Federated Commonwealth. Not so much if you were in one of the three neighboring states that got curbstomped in the process.
Sun Tzu Liao: Scheming, opportunistic weasel of a ruler, or brilliant political tactician?
Aren't those two things the same?
Awesome Yet Practical: Battle Mechs as a whole. Seemingly they should fall into the "Awesome, but Impractical" theme if they existed in real life but think about this for a minute. The weapons that 'Mech use can be mounted on tanks, track, turrets or even artillery pieces, but the size and power of the weapons would require a large crew to operate, portable generators and cooling units that would probably be exposed and often a set up time before they could be employed, not to mention a tear down when they needed to be moved. A single Battle Mech only needs one or two pilots, can carry 4 or more of those heavy weapons and the needed generators and heat sinks inside an armored shell and doensn't need to set up or tear down in the middle of battle; the walker aspect of the 'Mechs allows them to operate on any terrain wheres snow, swamps, deserts, mountains and hill can impede different kinds of vehicles, add to that the fact that 'Mechs can stand up from falling over and suddenly the incredible cost is justified by the mobility and durability of normally slow and vulnerable heavy weapons.
Broken Base: The Double Heat Sinks. Either you think that they unbalanced the game in favor of energy weapons or you think that they made the energy weapons viable. And whatever group you belong to, it is almost universally agreed that trying to fix Double Heat Sinks would cause more problems than it solves.
Complete Monster: Stefan "The Usurper" Amaris, who manipulated young Richard Cameron- heir to the Star League- into a conceited self-righteous Jerk Ass for his own political ends, and pretended to be his sole friend only to betray and murder him in a coup that ended humanity's golden age and replaced The Federation with a brutal tyrannical dictatorship that ruthlessly persecuted many groups of citizens, including intellectuals and artists. All in order to satisfy his lust for power. By the time Alexandr Kerensky and the Star League Defense Forces invade Terra to overthrow him, he has become completely insane, and even more evil, resorting to such unsavory tactics as using innocent civilians as human shields. So yeah, he's a major douchebag.
The Word of Blake during the Jihad. Dropped nukes almost impulsively, targeted civilian populations with bio-weapons... ALL the powers in the Inner Sphere pretty much went Enemy Mine against the Blakists, and much escalation occurred in response.
Malvina Hazen is edging towards this; certainly she's Axe Crazy already
The Society during the Wars of Reaving. They wiped out entire worlds with biological weapons and pretty much acted like the Word of Blake on a smaller scale; only with horrific human experimentation instead of reeducation camps.
Katherine Steiner-Davion grew into this. She believed that her brother Victor would make for a disastrous Archon-Prince, so she assassinated her own mother to force him onto the throne early and start discrediting him. When Victor made a disastrous decision that led to the FWL and the CC declaring war on them, Katherine pulled the Lyran half of the realm out from under his control to keep it from harm. That was pretty much the end of Katherine's benevolence to her people; from there, it was a short trip to crazyville. She started bullying her own nobles into compliance via either loosing LOKI on them or withdrawing army support for border worlds, leaving them defenseless before the Jade Falcons. Then she pilfered the rest of Victor's realm from him, ordered an assassin to kill Victor's girlfriend just to spite him, and then murdered her youngest brother just because of what he might say. Unlike many of her nasty contemporaries, Sun-Tzu Liao in particular, most of her later actions were entirely self serving and did not have the aim of helping her realm or people.
Incidentally, her older brother's girlfriend? Princess of a neighboring realm of considerable size, power, and military prowess. If the Draconis Combine hadn't had its own problems to deal with Katherine would have had a lot more trouble on her hands in the midst of the Civil War.
Designated Hero: When you think about it, Hanse Davion got a few hundred million people killed to impress his hot eighteen year-old Nordic wife. And to get payback from the man who tried to kidnap him and put a doppelganger on his throne.
The closer you look at Natasha Kerensky, the less you see a Fiery Redhead who is good at what she does and much more someone who is at best a Blood Knight, and at worst a Sociopathic Soldier (though to be fair, she would have been a type 4 after her lover was killed in cold blood) — the accounts are legion of epic (and lethal) bar fights that The Black Widow and her Black Widow Company engaged in out of sheer boredom and for the fun of it. Another account concerns a member of Wolf's Dragoons admitting that he had leaked information that made its way to House Kurita, information that contributed to the Pyrrhic Victory that the Dragoons endured on Misery. Natasha cold-bloodedly killed him, just as Jamie Wolf was about to slap the man. When Wolf called her on her murder, her response was to quote words used by Nicholas Kerensky to justify the complete annihilation of an entire Clan.
Game Breaker: There are some 'Mech designs that rather tedious to fight against. A most notorious example was the Clan pulse laser/targeting computer combo that practically guaranteed hitting your target. Land-Air-mechs in hybrid mode where practically unhittable. Under Solaris rules (extreme close combat for arena battles), multiple machine guns could reduce a 'Mech into scrap metal in short order, without generating any heat points. In most gaming groups, those things where countered by house rules forbidding the use of such designs.
Before the new rules removed the bonus for them, Rotary Autocannons found themselves mated to Targeting Computers quite a bit. The ability to put up to 30 points of damage on a targeted location, or even at a hit bonus, proved to be overwhelming, and as of the Total Warfare rules, rotary and Ultra autocannons at anything beyond single fire mode can no longer make an aimed shot, nor can pulse lasers. They still get the standard fire targeting bonus, though.
They Changed It, Now It Sucks: Many players reactions to the Dark Age period, especially the releated CMG. The reaction was far from universal, however, with the CMG not only bringing in new players, but many older players enjoying it and the changes to the setting. And, in all fairness, this has been a reaction to just about any change to the universe or game.
What Measure Is a Non-Badass?: Clan society is a strong in-universe example. If you're not badass enough to essentially bite and claw your way to the top and hold your place there against would-be challengers, eventually your fellow Clanners will start to consider you a liability to the Clan and start looking for your replacement. Clan society by and large puts little value on human life as such — it's how much somebody contributes to the Clan that counts, and with the warriors on top and naturally seeing themselves as the ones doing the most important work, it's no surprise that Clan civilians are usually considered second-class citizens and can be deployed, expended, or claimed as spoils of war as the warriors see fit.