I don't just mean the appearance. For instance, I don't like having to click and item, hit sell, then click arrows on the quantity slider then hit ok. Something where I could just shift+click to automatically sell items would be great. Or at least let me use the enter key to confirm.

For easy selling you can try Toggable Quantity Prompt, for quicker exit/confirm you can try Menu Escape or QZ Easy Menus.

P.S. Sorry for lack of links, Nexus seems to be a bit slow (probably only on my end).