meleebrawler
Smash Hero
It's pretty hard to have a continent-wide revolution without a war. Sometimes war is a necessary evil.
Edelgard isn't a villain, but a revolutionary. That's not to say she's morally righteous. Not at all. But she's not a villain. To call any of the house leaders outright villains undermines the moral ambiguity of the situation in an attempt to make it like any other Fire Emblem conflict. It's fitting a square peg in a round hole, and it's likely part of why the series rarely does true moral ambiguity: because anyone who isn't the paragon of virtue gets labeled as a villain due to some folks' insistence on maintaining a dichotomy, a binary that doesn't need to exist.
The Church of Seiros is literally run by clandestine lizard people who execute all those who go against the church and censor what information is available to the masses if it doesn't suit their agenda. They also keep possibly the strongest standing army in all of Fódlan. Rhea herself directly slaughters civilians in the final battle of the Edelgard route, something that NONE of the other house leaders did. She's judge, jury, and executioner when she's qualified to be none of those.
Edelgard's goal is simple: undermine the church, unite Fódlan by force (because no other way would work), take out Rhea, and do away with the current system of nobility in favor of a meritocracy.
We see and hear firsthand the effects of the church and the social crest hierarchy. Lonato, Miklan, Edelgard's own backstory, the atrocities committed by Ferdinand's father, Hubert's father, AND Bernadetta's father, the living conditions endured by Dorothea before she got discovered by the Opera, literally everything about Lysithea...the list goes on.
Rhea had to be removed by any means necessary. Edelgard, regardless of route, just happened to be the one to light the fire under everyone's collective butts to foster change.
Also now that I'm done with Edelgard's route I can focus more on making her moveset while I play Claude's.
Rhea also has an unpredictable time bomb in her split personality of Seiros that will dragon-nuke everyone if she gets upset enough for any reason. Letting her have her way may placate and delay her onslaught but who's to say the people who try to diplomatically change the system won't eventually cause her to flip and kill everyone anyway?