I'm a big fan of most of how AD works and looks now, but there are some functions i'd love to see:
Tabs in 'separated mode' windows. Sort of like browsers work: you can have any amount of windows, with any amount of documents/tabs in them.
Fullscreen mode to maximise working space.
Same for Hide palettes/UI shortcut, sort of like TAB in photoshop.
Dark menubar for OS X Yosemite.
Custom palette designer: put random icons into a new, custom palette. I'd love to combine most used toolbar, transform, align and boolean icons into a single palette.
Keyboard shortcut remap: tools (!), functions etc.
Updatable smarter embeds: place document A into a document B, edit A and it's updated inside B.
And a really big one:
Automation. Think actions in photoshop: record any buttons/shortcuts/canvas operations into a macro and play it any time using a shortcut. Could be only menus at first implementation, then add palette buttons and then canvas operations like drawing, transforms etc.
Keep up mind-blowing work you've been doing on AD, going at this rate this is going to be a no-brainer first-day purchase for any graphic designer.