I dunno, after 6 hours of playing the SP I gotta say it's kinda underwhelming. I don't know what I expected, but yeah. It's not bad but not great either.
Pros of Bannerlord:
+ Can execute prisoner lords
+ AI seems smarter
+ graphics, obviously
Cons
- more to do than in Warband, but still not enough IMO
- character models are weird, seen a lot of bald children and teenagers
- the quests are repetitive and kinda boring
- crashes.