This game is very nice and I'm enjoying it a lot, but I think this is by far the most clunky arpg I've played and it takes away do much from the experience. One way to improve this is:
a) Adding animation canceling
b) Making some of the skills being able to be cast while moving, whether by making them like that by default (at least buffs), or by implementing a rune that allows you to cast while moving)

Edit: Forgot to mention duplicated skills; They should work like auto dash/dodge toggle: you gain an ADDITIONAL skill slot, that you can place your duplicated (and only duplicated one) skill and then gain access to it by pressing some key bind (eg TAB) and it switches between your main and duplicated skill.