God I never thought I'd be taking Halo's side in one of these.
Mostly because the first one wasn't written well enough to be engaging and the second one made regenerating health seem acceptable.
In the days of Call of Duty, (and with Half Life 2 Episode 3 seeming more and more like it's never going to happen) the newer Halo games have been the only Bastian of fun shooters left to blow off steam in for 3 reasons.
First and most importantly no cover mechanics. If you were taking fire you just had to deal with it champ. Run, jump 12 feet in the air, shoot back, something that wasn't sit on your ass and wait for the enemy to reload. It kept a real flow in gameplay and it's fun! Remember that? Of course you don't Modern Warfare killed it.
Second Forge Mode. Halo has always been good about fun multyplayer maps but now you can edit them, and if you're skilled enough you can make a map and gametype that doesn't even feel like a shooter, or anything else you do in Halo. Like Whack a Mole or Grifball or Achievement Hunter Horse. Those are games where the map is the game type.
Third and most relevant to the thread is balance. Halo is the only balanced multyplayer game that exists. There are like 10 weapons and they're all very different. most importantly you never had to unlock anything. All the weapons were available on the maps from the word go.
In Halo 4 it seems like they're taking this away in favor of some CoD-esque load-out system.
And if everything is unlocked from the start then, well one step backwards one step forwards I guess. But if I need to get to level 20 before I can use my god damn DRM (Or Battle Rifle, or what ever they're calling it this time around) then Halo's multyplayer is done.
Oh well, I never thought I'd be sad to lose Halo.