Amen. Lights won't just charge at you waving their knives.
+1
I say:
Lights --> Objective focused, sneak tactics, supporting heavies in order to deal damage/defend while trying to go for the objective
Heavy --> Damagetakers and dealers. Supporting lights trying to accomplish their objective
Medium --> All around, covering distance between heavies and lights and supporting them both
Edit: That's what teamwork's about. Supporting eachother.