That could work too, but for many people, being able to dodge/avoid hits is exclusively the DEX bonus to AC, and they believe it doesn't have to do anything with hit points.

I'm on two minds about that: On the one hand, it's true that you're far better at dodging in lighter (or no) armor. OTOH, I agree with you that experience teaches you to decide where you're going to get hit if at all. So it might be something like "raise your arm so the strike doesn't hit your belly".