So, I won fair and square on turn 68 -
Mahina was the real MVP for some reason -
I think Mahina was able to do so well because she had a T4 weapon, the one which deals AoE damage x3. I also had it on Shae Mara. All in all, it wasn't as bad as I thought it was going to be, but I suspect it's because the empress swallowed 2 of my enemies, Mahina defeated 2 others and I the rest. I took out Zarai's capitol while Mahina killed Zarai herself, though. There really should be a way to get more movement points in the higher branches of the tech trees. Most of the tedium of huge maps is getting to places and spamming that end turn button. The hardest armies to deal with were Givori Ardelli's stacks of Psynumbra T3s. I kinda think they are the best T3 units in the game, they have insane damage (basically one-shotting anything and that's with the shitty mods the AI tends to use) and are a bitch to kill. The Autonom armies CORE sends after you were never really a problem, but I anticipated they potentially could be if left unchecked, so I made sure to clear every spawn point and keep a defensive stack in my main base to take care of any stragglers. Their units only ever became scary once they started getting T3s like Justicars and Avatars, but the map was pretty much over by that point anyway.
The campaign itself is very meh, probably worse than AoW3's base game campaigns, but at least your heroes can't get as freakishly overpowered and solo the entire maps by themselves. Assembly 2 and Syndicate 2 were unplayable and I used cheats to get past them. I liked how your secret techs change depending on choices you made on the first map (with the exception of the Vanguard [and Syndicate?], you can't be anything else other than Promethean in the second map). The things I didn't like were the random nature of the maps, the honestly incoherent narrative (I still have no idea what was going on and that's not because I was playing in Spanish), the lack of conflict on most maps (it's good that you have a peaceful way to win the map, but that doesn't mean there shouldn't be any wars going on, it just means you don't have to destroy another faction to win), the Amazons and how unnecessarily big some maps were. All in all, I doubt I'll ever replay it.