I want it to become much more complicated again. I love Civ, have done ever since the very first one. The 2nd was the best imo, since that was before they started dumbing it down for the mainstream.
It's too easy to do well with minimal effort now. I want a tech tree the size of Civ 3 at least (IV had a horribly small tech tree imo compared to its predecessors, making each game alot shorter
)
Create leader/civilzation modes would be baaad, because you could just select the 2 best traits and would destroy the balance the game has, which wouldn't be good. I'm happy enough being able to rename all the leaders/civilizations to whatever you want before you start a game.
Civ: Rev was awful btw. Being able to finish a game in 2 hours is real fail, silly them dumbing it down majorly due to console gamers not having much of an attention span apparently.
... /rant