I was wondering about MP as well. I'll probably never do much MP, except with my friends, but it's still important. They did the MP test beta a while ago, but it was pretty much just a "let's make sure this works" type of test, not anything serious. Then it was disabled, and I'm not sure if it's back yet with Beta 4 or not. All the best balancing suggestions come from the MP people, because SP people don't care if some thing is unbalanced, as long as it is in their favor.