B&W wasn't to bad up until around mission 3 where it got extremely repetative. By then your creatures pretty much huge, has learnt all your spells and know's how to behave. With the pet really being the only thing that kept the game interesting for me (because the missions were repetative "i lost my dog...my cats stuck in a tree...that bolder's blocking my view of the ocean..." ).
B&W2 I htink is going to have the same problem, I'm only in the 2nd or 3rd mission (can't remember which) and thats from playing it for about 4 hours on the first day I have it. The mission's are still pretty simple and from reviews they stay that way. And the enemy AI isn't all that great...Guess this ones going back on the shelf :p