I'd say Warhawk is a completely different animal.
I would say if you really like to play MW/2 as a team based game, then you should love it. K/D ratio is buried in the stats. It's all about points from capping and holding flags, healing or providing ammo to teammates, repairing vehicles, etc. The first one only had 2 game modes (only 1 when it launched), so that seemed to be a gripe for most. It launched with a demolition type mode where you would set off explosives to move to the next part of the map, and later added a domination mode.
I think the main complaint of the first is that the controls are slightly different in that it takes a little time shaking the twitchiness of MW/2 into something that has a little more weight to it. Have you played BF:1943? If you have, they are very similar, although the 1943 controls are a little dumbed down. It's very easy to pick up, you just need to put a few hours into it to start being successful (I think a lot of people forget how many times they died when they first started playing MW).
I think the best part of this game is the availability of classes - medics, engineers, snipers, etc., with a good balance being key to successfully winning a game. The maps are huge, so vehicles are a necessity, and they fit in nicely. There are APC's, Humvee's, quads, helicopters, stationary turrets, UAV's, etc. There are different loadouts you create for the classes, so it's similar to MW in that area as well. I'd say the biggest thing that MW2 has that BFBC games don't are the killstreaks.
I played the BFBC2 beta on PS3 and it was a blast, and a lot more polished then the first. Not to mention that this game is going to have a 4 vs 4 vs 4 vs 4 squad battle game type. Sounds like a lot of fun to be had there.
I think a demo is being released the first week of February - hopefully it's a multiplayer demo so you can try it out.