People don't play Rhoads or Kellys for the ergonomics. What are you proposing to change exactly that'll fix this? Fill the one of the body wings with lead?
rhoads : just place the strap pins further apart from each other (at the tip of the long horn for example)
kelly : bigger body (like it used to have, like, 30 years ago) and again, strap pin at the tip
done.
I do play my RR for ergonomics. I find it much easier to play than a superstrat or any common shape. it's just not as good as it COULD be with 2-3 minor tweaks.