Now that Treyarch is developing the game I have some hope of getting something new in the game... I still have yet to play CoD4 (well, I played the demo and it didn't impress me except for optimization-wise) but it still seems to be the same we've seen since the first CoD but this time in a new environment and with stats whoring. Theyarch is actually trying to bring something new to the series.
Not to say I would exactly love WWII after so many games but Pacific is something we've seen only rarely.