Short answer : Because its not balanced.
 
Long answer : i Think its not balanced because the Modern Warfare gameplay is designed to be very cinematic, with The Player being the badass special ops guy or the Hardened Marine fighting in the middle east, And to make it more cinematic,fun and to save effort with making AI Infinity Ward made the AI distincly inferior to the player to help this in single playerr, but this doesnt translate across to multiplayer where all players are trying to basically be the hero and i think this lead to the imbalanced multiplayer.
 
Why do you think the multiplayer is broken.

I don't think the multiplayer is broken. Questions should end with a question mark ;)

The multiplayer isn't broken. 

First I don't think the mulitplayer is broken.
 
Second, Your reason makes no sense anyway.  Everyone playing has the same chances or abilities as everyone else.  Its not like one team is Stupid AI types while the other is smart people.  They are all people, who can think and react.

That reasoning would mean the multiplayer of every game with a single player component is broken. 

It's not broken, just bad. Caters to simpletons.

I don't believe it's broken, or unbalanced.

I like how when people don't like a game, the call it "broken" because there's no chance that it could just be they aren't very good at the game. If anyone has something to complain about the multiplayer, it's the amount of glitches that got through. I personally believe that many of these could've been found and fixed with a multiplayer beta like the one they had for cod 4. However when people use excuses like "The multiplayer is unbalanced, that speaks more of your ability rather than the game's mechanics.

i don't really play anymore because i got into too many hacked lobbies back when i was playing.

It's not broken, but it's retarded unbalanced. I've moved onto Bad Company 2 since it's launch, but I randomly played a game with my friend for shits and giggles only to be decimated by dudes no-scoping with sniper rifles and eating us alive with Chopper Gunners. It's not an "I suck" case, I assume that considering I played it for 8 days worth or something and still manage to have the best k/d and accuracy rating on my friends list :/ My experience with the game is just dudes trying anything and everything to cheat their way into getting faster killstreaks. It's no fun. 
 
That, and I can't go back to any other shooter now that I'm so used to BC2's Spot button.

They just need to get rid of stopping power, then the game is perfect.

MW2 is not broken.
 
It's just not built with competition in mind. Once you get past that and realize that the game truly is all about just having dumb fun instead of skill based showdowns or special strategies you'll see why the multiplayer is actually pretty good.
 
If you wanna see balanced multiplayer and have your skill and speed be put to the test on a console, that's where you dust off that Halo 3 disk and pop it in. Or wait for Reach...

the game is kind of broken. the only problem with it is that the server connections. sometimes u will be playing and somebody will disconnect and the person who disconnected being the host. u have to wait for the server to pick a new host and if there is no host then it is just going to bring u to the lobby. after the lobby it will search for some more people. other times when searching it will say can't migrate host it will cause problems. some people have lag switches so if they are host they will just screw some people up. 
 
the game is completely fair in some ways. everyone has most of the same perks. when u unlock pro it adds little to the game play.

Who cares? The game is a pile of pig shit. I'll go play some good games thank you.

" i don't really play anymore because i got into too many hacked lobbies back when i was playing. "

The only thing that needs a lot of work is the spawn system.
 
They should also sit back and think, "Why is it that we have heartbeat sensors, chainguns on humvees, and indestructible shields... yet we still feature shotguns made in the late 1800's?"

Multiplayer isn't broken. The only time it ever was broken was the Model 1887s, but even then it wasn't a "no brainer gun" that people would use in all circumstances and scenarios.
 
If it was truly broken then millions would stop playing altogether. The MW2 fans seem to really be obnoxious (sp?) and seem to bitch just about every little thing, but here's the thing. THEY PLAY THE GAME ON A REGULAR BASIS! Its a stupid fan thing. Even a person like me who enjoys playing the game, vocally express my frustration over certain perk builds or the lag. I think it helps me calm myself by being vocal sometimes. Thankfully I only do that to friends and not strangers.

dual wielding shotguns, heartbeat sensors, one man army with danger close and noob tubes, knife attachments letting you fly around and stab people like the fucking sword on halo.... the list goes on and on and on

The multiplayer isn't broken, IW has simplified the gameplay for all newcomers alike.

The multiplayer is fun. Shut up and play! ;)

The Multiplayer isn't broken the spawn system has a few problems but thats about it.
Otherwise glitches, and hacks were brought about by a multitude of rampent hackers looking to break the game for no more of a reason they were pissed off it didn't have dedicated servers and mod tools.

I don't think the multiplayer is broken at all.  There are things wrong with the game in general.  But as long as it isn't an exploit, then a strategy is a strategy.  I never used an exploit once when I played, and was constantly on the top of the scoreboard, even when others were choosing to "cheat".  People need to stop whining and grow up.

I think the multiplayer is fine people are just way to picky
 
BBOYFLEX09  _ AoR Clan_ find me on Xboxlive :-)

I think the killstreaks ruin the game. 

You don't play as the Marines, you play as the Army Rangers or the 141. ;)
 
Anyhow, it's not broken at all. People are just very good at it which is why I can't play that game anymore.

It's broken because its terrible. 
And I wasn't bad at the game, I would have many +20 games but there's shit splattered all over the place in that game. 
There are way more fun games and its just way overhyped.

I think this thread is broken.
 
I don't really like MW2 though, but only cause I'm bad at it

@thedj93:

You win the Gold Star for living in reality and being honest.

" MW2 is not broken. It's just not built with competition in mind. Once you get past that and realize that the game truly is all about just having dumb fun instead of skill based showdowns or special strategies you'll see why the multiplayer is actually pretty good.  If you wanna see balanced multiplayer and have your skill and speed be put to the test on a console, that's where you dust off that Halo 3 disk and pop it in. Or wait for Reach... "

Im sorry  for youtube spamming in advance but THIS is one of the many reasons why multiplayer is broken: 
  

" The multiplayer isn't broken.  "

" I don't believe it's broken, or unbalanced. "

u guys cant even tell when a game isnt balanced =(

I don't know if I would say it's broken...but it's douchebag friendly. The commando perk, or as my friends and I call it...the Halo perk, is ridiculous.  Danger Close mixed with One Man Army and infinite grenades for noob tubes is terrible (As that one guy showed in a earlier post with that video). The heartbeat monitor is basically a camper's wet dream. 
 
And I agree it seems dumb to reward people who are already kicking ass the ability to kick more ass easier with killstreak rewards. At the very least kills earned during killstreaks shouldn't count towards your next reward. You should actually have to kill people with your gun to get it. Kind of  like how care package/emergency air drop rewards don't count.