The main thing to fix is the dang icons not showing up for assets downloaded from Steam when in game. Basically I dont download any assets other than buildings at this point, since they just become a jumbled sea of non-existant icons. This is single-handedly ruining the mod experience for many people. No point downloading 10 intersections when I cant tell them apart in game - just a sea of duplicate icons in the road menu. Aarrgghh.
Theres a few other top priority things that need to be fixed, including but not limited to :
1) completely messed up hearses and hearse pathfinding (and garbage trucks to some extent)
2) resource industry dying off (because everyone has the same rule : take the best paying job first - and everyone is super qualified equally since they all are PHD university graduates)
3) map resources (oil and ore) being used up way too quickly and giving too much money (make it last much longer, and give less profit to balance it out)
4) everyone living to the same approx age (thereby causing ridiculous death waves)
5) the asset editor locking elevated portions of roads so they are never modifiable or deletable after you save them (thus ruining all your hard work)
6) 4 lane one way roads
7) a reason to use different kinds of power sources (cost/mw means some power sources are basically useless)
8) Being a multi-millionaire mayor by the time you reach 8000 citizens (way too easy to be a multi-millionaire within an hour - crank up either maintenance costs, or lower tax revenues or a combo of the two)
But if I get only one thing, its the icons in game for downloaded assets that will make me happiest. At least then the downloaded assets will become useful. The rest is icing on the cake.
PS, since this sounds like a rant, I need to clarify that I love this game more than life itself (ok thats a little strong but you get my point) and the ridiculous amount of hours I've put into it. Paradox and Colossal Order are my gods and I bow to them and their greatness.
But theres some stuff that need priority fixing pronto and I'm calling it out.