[quote=@TaintedMushroom]Also what were your qualms with Korra? Character focused or world focused? NGL I like that one too but feel like all the characters were way weaker in depth than the ATLA, but I really enjoyed the ideas behind the world-building and some of the places they took things.[/quote]
[hider=Personal Gripes may contain Spoilers]I'm of the opinion that, as a CHARACTER, Korra was fine---she had issues, she changed as the story went on, she had some nice action sequences---but that as an AVATAR, she was terrible at her job and ruined everything for everyone. Other issues I take with it include the CONSTANT relationship drama, the direction of bending itself (I don't mind the idea of bending being incorporated into technology, but Lightning-bending is just something any Firebender can do now?), and the "progression" of the setting. It wasn't BAD, per se, but I felt like it was too soon---less than 100 years ago the setting was essentially Feudal Fantasy China, and now it's 1920s New York/Hong Kong with cars and radios and everything. I mean, I guess Meiji Japan made a similar sudden jump IRL, but I felt like the setting lost a lot of its "Mountains and Rivers" aesthetic.

Amon and Zaheer were top tier villains, and I don't hold the "rushed" nature of their arcs against them because Nickelodeon execs apparently hated anything that wasn't Spongebob and Fairly Oddparents at the time and wouldn't give the team more than 13 eps at a time to work with. The story of Wan was great imo, but season 2's main villain and his ultimate plan felt too fanfic-tier, and season 4 just felt like it took forever to get anywhere/had too many small plots that took space away from the main arc.[/hider]

[quote=@TaintedMushroom]I was thinking of two ideas, one being that the fire nation wins perhaps? Maybe a rebellion story?
OOOrrrr maybe they win but lose? Devastate the Earth Kingdom with Sozin's comet and awaken a sleeping beast as the Earth Kingdom as a whole pivots and becomes a brutal force to be reckoned with, even going as far as to completely flip the script and become the would be conquerors. 

I'm not married to any of these ideas in particular, just spit-balling so far.[/quote]
So an AU based on Aang somehow biting it, and presumably the next 2 or so Avatars who would've been born after him in the 100 year period before Sozin's Comet passed again also biting it? Or the AU Avatar simply being off somewhere leading their own revolution while the RP characters are on another adventure?

My recommendation would be to keep it small at least at the start---instead of our characters being part of some rebellion against the Fire Lord, for instance, maybe give us a Seven Samurai-esque scenario where we're trying to set a village free from a relatively low-ranking Fire Nation army-captain who has basically been made a provisional governor or something. Or defend a crumbling temple where a scant few Air Nomads have somehow escaped the Fire Lord's genocide, but their commitment to pacifism makes them a sitting duck to the soldiers hunting them down. Bring down a bandit gang led by a brutal Earthbender, or some Waterbending Pirates harassing a group of refugees on their way to Ba Sing Se via ship. So on and so forth.

Another recommendation I have is to look at Kung Fu/Martial Arts movies and think about how you might adapt some of those plots to the setting. For instance, maybe you take the plot of Ong-Bak: "In [s]Thailand[/s] the Earth Kingdom, an impoverished village has its most precious [s]Buddha[/s] Spirit Guardian statue stolen from the temple. The heroes must travel to [s]Bangkok[/s] Ba Sing Se to wrangle the statue from a volatile [s]drug[/s] Bending Steroid dealer."