I have a very similar problem. I accidentally figured out that selecting a skill and then pressing a number will assign the skill to that key, this has unbound my main skill from RMB, and now I can't find any way to rebind a skill to the RMB

Is there a way to do this?

yeah - seeing lots of issues with the keybindings setup.
First - if you switch something to something that is already bound - you get an error saying that key is already bound - but it switches it anyways so you don't know what the old one was bound to.
Hitting cancel doesn't stop the new key binding from taking place. It happens immediatly even without applying or saving.
Using a Dvorak keyboard the keybindings screen doesn't recognize the actual key that the keyboard is set to - it assumes default for everything - so for instance on a dvorak keyboard typing where on a normal keyboard the "G" would be is actually a "I" so when I type "I" for inventory the inventory screen does not appear - I have to type a "C".

The tilda apostrophe key (`~) can not be set to anything. I wanted to set my default roll to this as it's next to the 1 key instead of space key but it won't let it be set.

Someone just needs to spend a day or two going through and just cleaning up all the key binding code - with somenoe from QA with a solid test plan reviewing.

I agree with all of the above statements! I cannot revive EVER since I changed the attack in place IMMEDIATELY to spacebar, once i died...i could not revive. NOW I can't get the spacebar back as a revive! OMG this with down servers, losing faith fast!

I managed to solve my problem, putting here in case it helps someone
in the skill selection screen there are two ways to bind your skills. First select the skill (the horizontal bar), then
1. press 1-5, and the skill goes into that slot (and moves from where it was)
2. click and drag the skill icon to the skill slot you want to use
Note that you don't seem to be able to assign a skill to RMB with method 1, but you can with method 2 (just have to be very careful with the drag, it needs some polish)

Hello Devs I find it impossible this never came up EVER in beta or internal play testing. Now i cannot ESC back to the menu cannot revive, etc. none of the system keybinds work. The only binds that work are the ones to use skills and move, everything else doesn't do a thing i have to click the mouse on the system options, and when i die it's back to town every time.

Hi,
I have a similar problem. I changed the x key to something else and not i cannot speed up my deaths. I cannot find the option to key bind the speed up death button to something else. Please assist.