I want there to be more "minor crises" so to speak, like great Khan, that happen throughout the game and actually shake things up. Sometimes borders get pretty static in the mid game and it would be nice if there was more to cause some chaos. Things that actually pose a threat, too, even if it's not a game ending threat.

Better (and adjustable) random empire creation. Not just to tackle the spawn bias towards militarist empires or to deactivate certain civics (which can be done with mods), but to make the world feel more alive and to make it more idk immersive. I know this can be circumvented somewhat with pre-scripted empires, but they do not affect empires that form during the game (from a rebellion/split, Great Khan etc). This always bothered me in single player, the nations aren't just randomly generated, they also feel like they are.

I think making the Colossus tech not require the ascension perk would make warfare much easier for non-genocidal species. As it is, all the perk does is let you build a single ship with no combat capabilities that can trivialise planetary warfare, but only one planet at a time.

I think it should have an influence cost (discounted for militarists and maybe xenophobes) to build every time, while the ascension perk would allow you to have more at a time (maybe up to half your titan allowance), while also increasing your Juggernaut allowance.