Being able to sell singles at a higher price is an opportunity for higher profit for those willing to do it. Your idea has been brought up in the giant thread on this same topic, and the same opposition/support still stands for it.

Quote Originally Posted by Hiroradius View Post
No what the AH needs is a sorting option. So you can sort by single price, total price, stacks or HQ. There is no sort option so it just becomes a mess
It's already sorted by per-item price, I don't think it's a mess. However a sort option would be a nice touch.