The more I play it the less I like it. Most everything that is wrong could easily be fixed. The worst thing about it is the lag compensation, it's even worse than MW3. Half of the time people are firing at you as they appear on your screen, if you haven't experienced this then you are that person. I'm also quite sure I've been that person occasionally too. Kind of takes the fun out of it when you're on either end.
Next the SMG's absolutely need to be nerfed to all hell and back. Virtually everyone is running around with an SMG. Black Ops was pretty well balanced as far as weapons go, though the LMGs and the snipers (due to the maps more than the weapon) may have been a tad weak, this game is most definitely not. SMG's completely dominate. Due to typical map size I think the best way to fix this is with a massive and quick damage drop off rate over distance, rather a pure damage decrease or accuracy decrease. I wouldn't want to see their close quarters effectiveness hurt as that is their purpose, but they shouldn't be winning often at range.
They also need to allow all game modes to be played as hardcore in the standard ranked playlist! This is ridiculous....TDM, S&D and CTF only is absurd. Hardcore DOM and Demolition were two of the most populated game types in BO1. It's just stupid to limit people to softcore.