The left-click/right-click is a dilemma to me. It makes sense the way it is if I'm fighting with a sword and shield setup (left click to attack, right click to block, like in every game ever, even though you are holding the shield in the left hand). However, when casting two different spells or dual wielding anything, it's not as intuitive and it's confusing, since in that case no hand is intuitively the "primary" hand. And it becomes REALLY confusing when you're trying to assign items or spells to your hands and you have to right click for your left hand, you have to wrap your head around the fact that you aren't assigning a hand, but you are assigning a click-side you want for that item.
The developers were stuck though. There was no way they could get this 100% right. Assigning this dual-wielding system to a mouse was doomed from the beginning, and I knew it would be, as
I posted the day before release. I can't really berate the developers because there was no getting out of this sticky situation. There only option would have been to put more options on the control scheme to allow every player to do as the see fit (reassign left click to left hand and right click to right hand, which for me would still be confusing when using melee weapons and even arrows, where I'd have to left click to zoom in...). A good solution might be if we were able to reassign left click and right click to left hand and right hand, and just play a left-handed character, but I know I would find it jarring to be a left-handed person in a first person game.
No, really for me there is no easy solution to this, because sometimes the system works for certain weapon/spell choices, sometimes it doesn't, and a middling solution would make the use of the UI even more confusing.