Do you realize if that would happen, you'd loose alot of tanks making the queue times 2-3 hours if you're lucky...I have a strong feeling you and other people will cry endlessly more then "us" tanks, wishing and regretting you QQ so much about tanks rolling on what they're allowed to...
If its that easy(not saying its hard...) but why not queue as tank and get faster times and "more" loot ?