This kind of opinions are really useful when the render is in beginning stages. I have been tinkering with this one from 4-5 days and rendered about 15-20 tests. Right now i am not very motivated to do it again but i have noted your point outs. Next time i won't do these mistakes. Thanks!
The number of renders I've spend 20+ hours on tweaking every little thing, finally hitting the "Render this bastard" button, come back in a few hours and realize I've got something clipping through something else is TOO DAMN HIGH.
But yeah, always double-check their center of gravity and where it appears to be versus what they're doing. It'll be forward if they're running forward, backward if they're moving backwards, sideways if etc etc etc - and if they're receiving a hit, they'll likely be planting their feet as a steady base.
Which isn't to say a pose like that wouldn't work in a "SURPRISE MOTHERFUCKER" sucker punch, as it's unexpected and likely to knock the recipient back.