I was disappointed when I found out that CoD4 was not anymore in WW2, I thought that it will be crappy as Delta Force or something, but it really amazed me more than any CoD game before.
Now I don't like that they went back to WW2 but I trust the guys that they are the best war themed FPS games producers so I'm looking forward to it.
I also don't know how good the weapons and perk system will be, I mean... did they really have that many possibilities of weapon changing back there?