It's just you.
There IS no health meter, anywhere!
Kinda contradicting yourself there. Clearly there is no way to tell how badly injured you are unless you're near death's door because I've taken some serious damage without any warnings, palpatations or heavy breathing.
Basically, this makes for more realisitc behaviour by players... they may not die as easily, but they also don't charge at eachother because they have lots of health.
In multiplayer, perhaps, but it has entirely the opposite effect in single player. Players will just find a quiet spot and wait for their health to improve before going into the next firefight, and thanks to the heavily scripted levels, there are many such points.
Here we have a game which doesn't know what it wants to be. Having a health bar is unrealistic? So they remove it. I'm fine with that, but as I suspected, they've replaced it with a "hide in the corner and your health automagically regenerates" cop out. I can just about put up with that in Halo where you're wearing a fancy schmancy suit, but unless you're Captain America, bullet wounds don't just heal up in 20 seconds of hiding in a dark alley.