So far, in my opinion, with patch 1.06, Ak74u feels jumpy at long range. Accuracy has been taken down a notch, or two. Power seems to have been taken down a notch, or two, because it takes at least 2 extra bullets to kill someone (depending on your connection - lag has been factored in).
The Spas - The range on this gun has been shortened. Last time I remember, this shotty has a range of about 12 ft, now, you have to be almost in their face to kill someone. Too many hit markers that you would be MVP of Assists in a match.
AK47 - The most overpower weapon in all of COD series, has been underpowered like hell in this game. Maybe because of the variations of the AK47 of when they were manufactured by model type, but its crap. No recoil and the iron sights are horrendous. At least in MW2, the recoil was manageable and you could kill 3 people with 1 clip. Just my opinion.
If you have any Guns of Nerf list, post them up!