Only thing I see that really needs changing is a Cast Cancel function besides the GIANT cancel. If you have to click that, it takes away from kiting monsters and such.
As I've noticed and now experienced, the game has a problem reloading on some browsing formats. I had to clear my cache completely to reload the game in order for the start game button to show up again.
I've been playing the game for a whole 5 minutes, and I was instantly annoyed at the numerous clicks for menus instead of hotkeys. The game itself is awesome overall, and for free I can't complain. If you want less frustration and more enjoyment in a game, it's key to have awesome controls and customization.