The camera has a fixed angle to make it easier for the map and model designers.
Skills have cooldowns, and it costs nothing to press K and drag fresh skills onto the skill bar. You can use that to replace skills which are currently in cooldown. It wouldn't hurt to have extra skill bars, but I don't think it's that big a deal.
I guess so, but it's not very intuitive from a modern game perspective. The about 30° cone is painful for my playing habits. Can't speak for others, but it would surprise me if I'm alone on that one.
A good user interface shouldn't take you to a point where you do things that feel like a workaround. The modifier/qualifier solution sounds very good to me and the idea about up/down buttons to switch between skillsets sounds also good. At the moment the skillbar is very limited if you like to play a generalist, a character with many different skills. Reordering the skillbar every half an hour or so is a bit cumbersome imho. ^^
