[Idea] Troll's way to make people play different tanks

Dakiras: At first I thought this was a troll thread... the title distracted me and I was ready to charge in with sword and shield for battle.   But actually, it's an interesting idea and I'd like to see people's thoughts on it. I don't think it would be accepted as an idea, but I kind of like the thought of some diminishing returns on heavily favoured tanks. Have an unexpected +1, and I'll eagerly await further ideas. :)