A few upgrades I would like to see:

Chat:
The ability to add a sound (and turn it off), so if we walk away to say cook dinner we will here when we get a PM.

Runes:
Add a third and forth row to the main screen to minimize the need to hit sell all as much. Would save time and energy.

Fair or stock exchange:
The ability to exchange our items back also for gems at the same exchange rate that we would have to buy them at, including cards.

Guild:
The ability to sell our items to our guild mates (with an imposed trade amount)

City:
The ability to turn off experience/training completely when in the city.
The ability to sell unused mounts back or have an upgrade discount when trading.

General:
The ability to minimize icons similar to to the ability to minimize your quest info on the right of the screen.