I've played this game a bunch since release. Overall impression is that combat has improved a lot since warband – the battle AI is much better, staying alive is overall significantly harder (mostly because the AI can actually aim in this game), graphixx are pretty (if you care about such a thing anyway), and I can have a 500 vs 500 units battling it out simultaneously while the game runs better than 150 vs 150 in warband.
On the other hand, everything not-battle experienced a massive downgrade. The economy is a joke, the AI snowballs super fast (hell, it often starts before you even get your first fief!), AI is all kinds of retarded in many different ways, there are broken systems galore, nothing seems balanced at all, and the quests... Yeah, okay, the quests are just as shit as in Warband, no downgrade there
There are also new features added, such as minigames in taverns (who the fuck cares???), being able to have a kid (uh, okay?), and being able to kill enemy lords (YES! FINALLY!). There's also a kingdom management system that seems interesting but needs quite a bit of work before it stops being gamey and kinda stupid.
The good news to take from this is that all of the bad shit seems to be contained in the campaign part, and that part tends to be the easiest to mod, or such is my impression, at least. I truly believe that mods will be able to turn this game into a 10/10 experience, just gotta wait for them to come out (I have my eye on In The Name of Jerusalem II, and Shokuho). As for the base game... It's fun when you just want to go and fight some battles, just don't expect anything more from it.