Crossworlds had a lot of replay value as pretty much all stores were completely random. Your hero didn't start with a set of armor taking up 4 spots like in warriors of the north. It's almost not worth trying to find another set to put in instead. Your companion's in crossworld also allowed for much greater usage of artifacts than in warriors of the north.
Crossworlds was the one king's bounty that actually was a bit like the original game (which I love and still play now and then).
There's just way too many boring fights and you level up a lot slower. You level up like you did in Legend. Crossworlds had it figured out. Fewer fights, more dynamic. A lot more bosses. Running back and fourth questing is just not a fun thing to do. Or figureing out where to turn in quests. It really became tedious
I was really annoyed with the usage of Legend maps as well. It comes off a bit lazy to me. I would much rather have discovered a great new world.
And what is up with removing the lizard race? So they took that race out and added vikings. I find that sad. More units = more fun. So no reason to remove them, especially since they were actually more interesting than the vikings :-/. In fact I was very disappointed that so few new units were in the game. The ice dragon was a nice touch, but still.... I was hoping to discover a whole lot more.
I really hope they consider starting from scratch for the new Kings Bounty release and then do a King's Bounty 2. I know all units take a lot of balancing and they are all very unique, so I'm sure it's hard to come up with new units/races, but it would be worth it