Height was something I considered and something I may add at some point, but the challenge with having these things being distinct dimensions is that even if I only added 4 height levels, I'd have to generate over 1,000 more images representing the character!
I may just end up making one particular character where that's how they express Vitality or Strength, or maybe have a wildcard attribute that gives more flexibility here without having to combine it against all other traits.