There should be no custom settings for speed,jump,gravity,blah blah blah. There should be one basic setting that you can't change just like halo 2(use there settings.) The reason I say this is because from H3 - H4 MLG playlist was so different in settings from the regular playlist that is split up the community. For Matchmaking it should go :
Team Slayer(Ranked 1-50 AR start)
______________________
Team Objective(Ranked 1-50 AR start)
_________________________
Team Hardcore(Ranked 1-50 which would be MLG settings)
________________________________________________
Team Doubles(Ranked 1-50 BR start)
_______________________________
Team Snipers(Ranked 1 -50)
________________________
1v1(Ranked 1 -50 Br start)
______________________
Big Team Battle(Ranked 1 -50)
_________________________
Clan Wars(Ranked 1-50 4v4,8v8,16v16)
_________________________________
The social Slayer and objective.