hi, if you could move the upper horn's strap button somewhere alse or/and add some thickness to the body to increase the weight that would be nice
you could also do some multiradiuss necks , rounder at first frets and flatter at last frets
the popular 400 radius for a lot of guitars for power chording is not the best decision
and last, but not least make fatter necks for 25,5" scale 7 strings, the ax7221 has wonderful neck(nice 21mm with 300 radius) but is unfortunately unbalanced,22 fret and 24 3/4 scale. if you could make a rg style 7 string with the ax7221 profile but just in 25,5'' scale and 24 fret i think that it would be great