A few thoughts on this...
1) I was a bit disappointed not to see one of the better reasons not to click every ability on your bar, and that is that regardless of how fast you can click, you cannot possibly use a targeted AoE as quickly as a keybinder. It's simply not possible when a person using binds can have their mouse already in position before pressing the actual ability. I will also note that because of the GCD, in a lot of situations, clicking can be just as fast as pressing binds (mouse or keyboard). I actually used to click in my early days of vanilla, and I was just as fast as anyone else and even PVP'd (including interrupts, blinds, saps, etc) with it. The situations that usually caused a problem with clicking were, as I mentioned, targeted AoE.
2) You should include that it is usually helpful to keep certain types of abilities constant between characters. For example, on all of my characters, if they have an interrupt, it goes on '5'. If they have an offensive magic dispelling capability, it goes on Shift+'5'. Defensive dispelling is assigned to shift + left click via Clique.
Keybinding is a very personal thing... some people simply have certain keys they prefer to use and others would never want to use them. I have a friend that binds to the F# keys, which I would never want to, because I prefer not leaving my comfy little WASD area . In my case, I prefer not rebinding 'Q' and 'E', simply because sometimes I actually use the turning when I'm using my right hand for drinking or whatever. Although, I definitely recommend rebinding 'A' and 'D' to strafe... for the longest time, I used to leave them as turn (used 'Q' and 'E' for strafe) and then went back to playing some FPS games... yeah, that didn't go over so well .