Since this game is called Mechwarrior LL, obviously I want to see Battlemechs to be the dominant force on the field, otherwise we might as well go play BF or other 3rd person shooters.
In 16 vs 16, it should have at least 8 mechs, with other arms divided among the remaining 8 slots.
8 Mechs, 4 Tanks, 2 Aero, 2 Eles.