At guns and infantry can be seen at extreme ranges even with basic infantry, that makes tanks and other vehicles much better investment than it should. Coupled with pinpoint accuracy of planes this could be the issue. 120 point 17pounder for exaple can be killed with 1 bomb plane and if you have a little bit more air than enemy this action will go unpunished, meaning that the only thing you got to stop tank is TD and High caliber tanks of your own. AT guns are really risky investment, that can be stopped usually even without counters(for exmpl if tank or haltrack suppress it). and while infantry can be ok in forest and urban areas their movement visibility penalty is too harsh and they can be seen from whole map. If you use recon AT guns also can be usually seen at 1200m even when hiding in yellow bush cover, which kinda defeats their purpose.