"easily spammed"? Did it not occur to you that the cost for a Pershing will be at least that of Tigers/IS2s. So in almost no games ever will the US have enough resources to consider getting a second big P.
It wasn't exactly uncommon to see more than one IS2/Tiger before the limit was enforced, otherwise it wouldn't have been necessary. Barton has a point, though it wouldn't surprise me if they just released the commander for the $$$ and said the limit workaround was 'intended' or 'unavoidable' or whatever.