It would be nice to see more of a focus on fixing the content that 4.0 and subsequent updates have broken. I get that there are balance issues to be tweaked and optimization to be optimized, but more of my builds get shafted by bugs and broken content than not. For instance, in my most recent game I played a Fanatic Spiritualist/Authoritarian empire with Psionics ascension. At some point in the game, all of my main species leaders lost the Psychic trait, and also my thrall worlds froze all population growth, rendering the tech useless. It's still a playable game, sure, but it's lousy with bugs and content that just doesn't work anymore.