Lol the discussion's been brought here?...was a matter of time i guess...*sigh* i'll just quote myself frm the GFW thread (with edits for clarification) :
Yeah that was the only "gripe" I had with the game....despite being put in a variety of settings, i hate how the game sent enemies in infinite droves...feels like you could only progress if you plough your way through, physically "capturing" one area at a time, in which doing so seems to switch off enemy respawns within your immediate vicinity, making them pop up elsewhere ahead...on one hand I like that you're thrown in a constant battle, but on the other,you can never rid an area of enemies from a distance (because it requires you to actually go there and stop the respawns)...
I suppose IW wanted to maintain the somewhat realistic nature of the game and not put you in a role of Rambo like in other games...where, say you're given a sniper rifle and you pluck the enemies out from afar one by one until that huge area ahead of you remain absolutely devoid of life (since enemy count is finite)...and maybe IW figured if you're gonna invade enemy territory, you should be expecting no less than hundreds of hostiles in the area....in which case i understand their rationale for those infinite respawns, but still, I'd have liked them to tackle that situation by having enemies turn up in an irregular timing (so it feels like an area has actually been CLEARED even for a short while) and definitely not from the same goddamn spot/house/barracks...have trucks/helicopters ferry them in or something...