I use an Xbox One controller when playing relaxed content and keyboard+mouse when I need peak performance. Recently I've also acquired a foot-operated controller which I use for movement, reducing the need of finger acrobatics for my left hand in complex raid situations. So now it's pretty much feet = movement, left hand (keyboard) = abilities, right hand (mouse) = camera and occasional targeting.

On the keyboard I find that number keys past 6 are too far from the left side where my hand usually is, which makes them difficult to hit accurately. So I've remapped the movement keys from WASD to ESDF and made the hotbar shortcuts go around that cluster as ZAQ123456TGB. This gives me 12 hotkeys that are in easy reach of my fingers at all times, and another 12 when used with the control key. I've also mapped the side buttons of my mouse to a few extra hotbar slots.

You don't need hotkeys for absolutely everything. It's fine to activate out-of-combat abilities such as mounts, teleport or emotes by clicking. Two hotbars (24 slots) seems to be enough for the combat abilities of most classes.

I find that changing the movement mode to legacy (camera-based) makes it easier to move around quickly using the keyboard. You'll no longer have to worry about which way your character is facing. If you need to dodge to the left on your screen, you simply press the left movement key. The only "drawback" is that you won't be able to walk backwards (since your character turns to face the direction of movement), but this is almost never an issue.