1) Match making
2) Poor team performance
One thing that stood out was the pathological levels of anger displayed at poor teamplay. Losing is painful. Losing due to someone else's mistake is truly enraging. The level of hatred displayed on forum boards towards anyone contributing to a loss goes beyond simply penalizing the poor player with reduced earnings, or other penalties. Perma-banning a "loser" from gaming for the rest of their natural lives is one of the *least* hostile responses I've seen.
Then, the sun shone brightly, the fall foliage was on display, and it hit me:
The root word for fan is fanatic.
And, there is no fixing it.
Gamers, by definition, are obsessives. Online gamers are even more afflicted.
The two most dedicated online gamers I know are people who have medical conditions that preclude themselves from any other activity. One has a heart condition (and is yelling at kids on his lawn), the other one is (drumroll) certifiably crazy, because he has been certified. Can't hold down a job.
Naturally, his game is WoT.

There is no fixing said gamers. They want, and need, to win. Because, that is all that they have.
The best matchmaking system in the world cannot rectify this. Medication and therapy might help.
Competitive online games like MWO are prone to particularly humiliating stomps, due to sheer mathematics. It's no wonder we get the crazy uncles/aunts emerging from the attic or asylum onto the forums, enraged.
Negative motivators, like reducing earnings, only make the problem worse. A skills screening system, prior to joining a match, would only skew the distribution towards the lunatics, as they play the most. Clan Wars, anyone?
My suggestion to PGI is this: De-nerf earnings, reduce the grind, and make lots more content (maps, not mechs). The fanatics will continue to play, and the casual ordinary customer will be more likely to stay. Otherwise, Clan Warfare will split the playerbase into mutually unsustainable camps.
For the casuals like me, the Ignore button is a godsend. Use it. Ignore the crazies, and any taunting that you are a coward. You get to leave the asylum behind, they have to stay.
If PGI fails to deliver on making a better game, remove your payment methods. I did that to Wargaming.net, and have not regretted it. I walked away from those hundreds of real dollars spent, and I'm the better for it. I'm not holding down a second full-time job playing the game, now.
Many who claim that they have never paid for content are flat-out lying. PGI would not be in business if no-one (or only the whales) paid. And, they only have a limited amount of flying time left in the fuel tanks if they don't make the game more appealing to new customers.
If the game does not improve, do what the postage stamp says: Just walk away.
I feel much better, now.
