The minimod I've been thinking about some time ago just got released.

It tries to fix some issues with vanilla without making it too much of a different game. So things aren't as sluggish as in vanilla - movement speed is much higher, you can build every building in one turn if you have money. There should be less micromanagement. Factions are now more noticeably different in early game, as bodyguards got some massive nerfing and sieges (which make all units pretty much the same) got much harder. Details of what works, what doesn't, and how and why are in the blog post.

If you like vanilla, you might want to give it a try - it's just like vanilla except in higher concentration.