The hot bar is a mess, I agree. Especially for spell casters.
When selecting a spell, the combat is paused and I don't need to look at the screen, so I don't care how much the hot bar expands or pops up to make it easier to use. It's silly to lock it down to that one small area of the screen.
Slightly OT, but I wish some of the spell icons were more distinct. Some of them are hard to tell apart because the icon and background behind it are almost the same color, without enough contrast to see the icon at the tiny scale they're shown in the hot bar.
