Guess I'll chime in on the weapon balance discussion...
The shotguns are practically useless and are probably the weakest they've ever been. The removal of stopping power nerfed them across the board, plus it doesn't help that, aside from the SPAS, they're all poorly designed and impractical. The Olympia is useless if there's more than one enemy (or if they're more than 12m away), the Stakeout is heavily reliant on good hit detection and netcode (both of which Blops lacks), the HS-10 is a worse SPAS and the SPAS... at the ranges it's dominant in, you're better off lunging and knifing.
The sniper rifles are also practically useless. Mainly because of aforementioned stopping power removal. They're also wonky. I've been using the PSG-1 lately and shots to the center mass occasionally don't even register... it's not like I'm being shot at either, even with held breath they just don't register. I don't get it. (Actually, I do, see: hit detection and netcode complaints.)
SMGs, outside of the gripped AK-74, are all too weak and you're almost always better off using an AR. The gripped 74 is an exception purely because it's powerful, doesn't burn through ammo and doesn't have much recoil. Gripped Scorpion can also be good with scavenger, but then you have to sacrifice your first perk.
LMGs are basically less maneuverable ARs with none of the ammo/clip size benefits that LMGs usually offer. (Except for the M60 of course, but even then its use over a regular AR is pretty limited.)
Which leaves the assault rifles. Which are actually balanced pretty well overall, even though there's about three guns that stand head and shoulders above the rest (Famas, AUG and Commando).
I suppose my problem with Blops is that it's just boring there's really no reason to use any weapons outside of the ARs. MW2 was an unbalanced piece of shit with awful maps but the aspect that gave it longevity was the ability to use whatever wacky, hair-brained class you can think of and still do well. With Blops I try to use a shotgun or sniper rifle or SMG and get annoyed because I'm almost always at some sort of disadvantage purely for using those weapons. It gets old after a while.