Overall Aion has a general, clean, and user friendly interface, which has a combination of features from many previous mmorpgs. However, here are a few things that Aion has improved on compared to previous NCSoft games such as Lineage 2, Guild Wars.
Hotkeys Bar:
Looking back through the history of mmorpgs, many of them have had your standard one row hotkeys of 10 – 12 hotkeys shortcuts. One really cool Aion's feature is that the game has the ability to have up to 3 rows of hotkeys bars of 12 keys at once that is 36 slots for your skills, macros, and tool, with so many slots there is a much less need to switch between hotkey bars.