It'd also be a lot less cluttered if specific sub-panels were shown only when they're relevant; i.e. there shoud be no UI panels for command-buttons or unit statistics unless you have a unit selected. but if that proves to be too confusing, as in panels appearing over previously-accessible units, maybe it should be made into an explicit toggle, with some hotkey to turn the panels off and back into view at the user's will.
Here's a guess at how the UI might possibly be improved:
booger from StarCraftWire.net had an idea of a more rearranged interface:
In the end, it might be best for both Blizzard and the players to have an "officially" (as in, without resorting to unsupported and possibly illegal hacks) modifiable user-interface for everyone to customize according to their own tastes.