It is a worry that they have tried to add too much on something that worked well enough anyway. I suppose it's to get away from critism that it's just another map pack.
A few of the weapons needed better balance, the skorpions should have been dual weilded with hip fire otherwise they were pretty poor.
I will jump straight into the MP though, won't bother with the SP game until after xmas when there's little to play. I've got the week off after the game is out so will just batter the MP before everyone learns the maps too well