I play WHM with controller, and love it.
Getting actions off in-time and on-target is essential to completing content. I find the best solution to be reducing the average number of keystrokes needed to get any of my actions off on any target. To that end, I focus on using effective macros and efficient keystrokes.
Use macros that combine utility actions with spells, such as Swiftcast Raise, or Swiftcast Surecast Medica. This allows me to remove Swiftcast/Surecast off my XHotbars, freeing up valuable slots.
The other half of my strategy is efficient keystrokes, which really goes hand-in-hand with effective macros. The fewer XHotbars I have to cycle through, the faster I can get to my desired action. @L50, I run with two XHotbars to house all my actions, and of those two "clusters" are identical (My L2+Buttons and R2+Buttons have the exact same actions such as my Cure Line and CC/Hate Management). Doing it this way, I have far less action positions to have to think about in the heat of the moment, reducing my reaction time.
The simple solution I've used to get around finger fatigue:
Don't put Hotbars on toggle, instead, train yourself to not hold down your L2/R2 buttons all the time.
Essentially, when I go to use an action, I quickly hit L2/R2 a fraction of a second before I hit the D-Pad/Buttons for actions. After a bit of practice, it's **** near automatic and my fingers don't get tired of holding down a trigger all fight.
This allows me to still use the D-Pad up/down to target party members, or left/right for mobs, which I find to be more than sufficient to get te job done, while reducing my overall reaction time.