Hehehehehehe..........Oh boy, what I'd like to say!!!...... Hehehehehe!!!!
Nose
Get rid of:
Toenails, wisdom teeth, appendix, tonsils
Improve:
More robustly designed knee and shoulder joints, thicker spine construction, better eyes (comparable to an owl), better range of hearing, better immune systems, earlier developing frontal lobes and, considering the earth is 72% water, maybe some gills.
His brains. So that he grows up to understand another human being and learns to live harmoniously.
The bladder to safely hold just a little longer! Lol!
i don't do any changes because god is so intelligent that he make everything beautiful and i wouldn't disrespect him
Better bones my arthritis is killing me
Well, this would be entirely self serving (due to my age) but legs that could be collapsible on demand so that I could pick up anything I dropped without bending over.
And of course, uncomplicated return to the original configuration immediately upon request.
(And this mechanism would never need servicing---and be 100% reliable.)
Sorry, I'm no better than Hippy, my first thoughts... "Come in Tokyo"
I think it would it would be easier to tweak gravity, stop everything from heading south and take the weight off our worn out joints.