I think this, in a nutshell, is the biggest difference between MW2 and BO. There is no Stopping Power perk, and you can definitely feel that it's missing. It's why you really need a high ROF weapon IMO.
I haven't really found a weapon I like yet.
Hardcore mode is perfect IMO. more tactical TDM games with quick kills. I hope they add HC CTF as they had in WAW although they have HC S&D