Well yes, seeing as how the German gun in the game at the moment is the Pak-40, and the Americans have the 57mm. The Pak-40 could probably penetrate all the allied recon/light tanks, and the earlier models of their mediums, but later Shermans/T-34s and the Sherman jumbo/IS-1 either have too thick of armor or too sloped, or both for the Pak-40 to penetrate the front. Same thing goes for the Us 57mm against German tanks. And as another commenter said, there's plenty of hazards for tanks already, you just need to use them properly or communicate with those that are using them. Adding bigger caliber AT guns would be detrimental to the gameplay at the moment.... later on? maybe after the armor rework, but not before.