This is really only the second Call of Duty game I've gotten deep into, the first being MW2. That game hooked me like maybe no other multiplayer shooter ever, and this makes minor tweaks that keep me coming back over and over. Support class really changes everything for me. I love it that I can help my team even if I can't string together a bunch of kills.
Single-player isn't great, but is serviceable. It can be beaten in one sitting and has a handful of the typical "wow" moments we've come to expect from Call of Duty.
It may be more of the same, but that's still better than most games out there.