Lame? I'll grant you that, but I don't look at it from a standpoint of proportion, I see the limits as absolute to mean that: at any given time with any given number of players, no more than 2-4 machine guns and snipers (accounting for drops at death) should be on the field. As long as those conditions are satisfied, the field of choice becomes fair play, however lame the choice is.
I definitely think limits are a good idea, though. Kalt without MG limits would be madness characterized by even worse stalemates and imbalances than we have now. Sniper limits... well, I'll take my chances against a sniper than against an Assault class running through the wheelhouse, the more the merrier (I tend to agree with Anni, this coming from a pretty decent sniper).