Based on some patches made to the main client and forks this are some ideas to implement:
-Import Keys
-Determine where the .dat and important files would be located
-Deterministic wallets generated with a strong password. No need to store the keys in the wallet.dat(16+ chars cap and uncap, numbers, and symbols)
-Vanity Generator, Miner, and bulk key generation.(Under a certain folder x ammount of keys)
-Show addresses already "linked" together in groups.
-Advanced Send(From, to, both with multiple inputs/outputs and a specific fee)
-Access control for the API, create users who can only manage specific accounts and/or limited commands.
Most of those are not really UI features but backend, you're better of lobbying for them for the core client. I think a some of them are already available as pull requests (such as deterministic wallets).
My project mostly focuses on the UI and improving the core <-> UI communication.
For usability make a divide between: Power Users/Simple Users.
Power Users have low level access(Many of the futures described above)
Simple users are limited to tx historial/contacts/send and status/messages dumb down.
Indeed, there should be an "expert" mode which exposes some more advanced and debug options.
Will help as I can when I get my Ubuntu box set up again.

Cool

hey, why don't you use this quite beautiful iconset, which has virtually every icon you can think of (7600!!):
http://www.famfamfam.com/lab/icons/silk/Creative Commons Attribution 2.5 License, and the guy specifies that he has to be mentioned only on the credits page...
I think the problem with that icon set was that it only has 16x16 icons, which are good for some purposes, but not (for example) for the toolbar in many window systems.
But feel free to replace some of the small icons if you think they have better icons than the current ones (icons are in src/qt/res/icons..)