General

Been gone for awhile. Need explaining.

Hola,
So, I quit MS about 5-6 months ago. I am considering coming back though for the sake of having a game to play that's not console. These are my questions:
1. I know there was a "Big Bang" and I know that it balanced the game along with lowering the amount of EXP needed to level. What else? What classes have completely changed tiers (i.e. are NL still considered the "best" and Palis considered "not very good&quot?
2. I would be playing with friends from XBL. Is MS now completely solo based or will team work profit?
3. Can someone explain this new like.. 3 lines on a weapon stuff?
4. The "team" I would play with would be about 3-4 people total. What would be 3 classes that would work really well together, all 3-4 people being able to level at a moderately same rate. I would appreciate knowing a good 3 man team along with a good 4 man team If it helps, we would plan on going to 4th but it's not like we would grind

So yea, if someone could answer this, that would be totally awesome

EDIT: 2 more questions
5. Can you get banned for using Joy2Key?
6. Can you get banned for using Vent?