Just like to say: you guys are awesome (the majority, who hate on quickscoping).
What is the one greatest hate amongst Modern Warfare players (1 and 2).
Grenade Launchers, "Noob Tubes". Why? Because they offer cheap one-shot kills at most every range imaginable. Splash damage means (like the aim assist in Quick-Scoping) that one does not even require the aim to be on the target to score a 1-shot kill.
As has been mentioned more times than I am bothered to count, Sniping is a role, in fact, the word snipe refers to precisely taking out targets. How about we just add an AA-12 back into MW2 and might as well into Black-Ops as well, since they ignored feasible technology (which was fine), and give it its realistic statistics: drum magazine giving it far more rounds,and an effective range of just about any distance on most maps.
And how about those frangible rounds they like to equip it with, extending its range to 175 metres and making each shot basically a grenade round. Balance, my friends, is key in everything. Kill Quick-Scoping, long live Hard-Scope Shotguns (Sarcasm here, this would truly be bad)