Of course, the reason the current system feels so natural to me is primarily due to the fact that i use it on a regular basis and have an order in which to buy things that makes sense based on the current behaviour, i realise it's never going to be as fast as binds but it works well enough for me that i've never felt the need for binds. Any system needs to be simple enough that a user shouldn't need to resort to binds, items need to be in a predictable location on screen and preferably be accessible without any need for interaction beyond double clicking on an item, no scrollbars unless absolutely necessary.
This all sounds very negative, but i'm really not all that attached to the current system, we just need to make sure that any change is positive for those who actually use the menu, rather than just sounding neat to a bunch of experienced bind-using players.
Hmmm, that's all looking decidedly tl;dr.