I can't say things like "thats not how someone would shoot fire out of his hands or levitate" because that stuff isn't real.
I can however say "thats not how a person can jump/react with gravity" because these things exist in our world too. We want these things to be like they are in our world because it feels more like YOU (your character) are a real person in this fantasy reality.
Clearly, we should immediately sink to the bottom of any body of water we step into (and only be able to walk across the bottom of the water to get out) if we're wearing/carrying more than about 10lbs of light clothing.
It's more realistic.
:whistling:
(Seriously, though.... swimming in any kind of full body armor is a million times less "realistic" than the jumping in OB. Of course, I never got close to 100 Acro, so I can't comment on the "skip over the water" thing.)