It's slow at first while you get used to it. I played on a mmo mouse for years, and at first controller was weird (but I really wanted to sit back lol so I persevered).
Now I can't imagine playing scholar without it (in pve. In pvp, I switch back to mouse/kb when I'm playing seriously). I use 48 slots (even more than you lol) and it's SO easy to access them all via a controller setup like the one I have, and it's so easy to dodge things thanks to the analog.
I think you should reconsider it
But even if you don't...
You could probably make a 2-hotbar set up if you just don't have some of the less used skills (like dissipation or Sustain) at all, and you use the summon macro to swap out all pet skills.
Another way to come around it is to have hidden hotbars, and then reserve 2 of your main hotbar slots to copy them.
Example
Hotbar 1 - whatever skills you want, except #11 and #12 are going to be macros. This should be mapped to your mmo mouse buttons directly.
Hotbar 2 - don't bother putting anything there, this will be visible to you but will be overwritten. This should be mapped to something like Ctrl+button or Alt+button.
HIDDEN hotbars (show only while you are editing them). Because these are hidden, buttons do not need to be mapped to them.
Hotbar 3 - put skills here
Hotbar 4 - put skills here
Make 2 macros (which I will call A and B)
Macro A copies Hotbar 3 to Hotbar 2
Macro B copies Hotbar 4 to Hotbar 2
Put macro A on Hotbar 1 slot #11
Put macro B on Hotbar 2 slot #12
Ta-dah, now you have 2 macros to switch hotbar 2 into 2 completely different hotbars at will!
What I'd do in that case:
Hotbar 1 = Common healing spells + Big cooldowns (you want to see your cooldowns) + switch macros
Hotbar 3 (hidden) = Attacking skills + Pet skill switch off + healing skills that didn't make it to hotbar 1
Hotbar 4 (hidden) = Summon skills + Pet management skills (because both of those would be lesser used) + whatever else didn't make it to hotbar 1 & 3
So while you might need to use multiple hotbars, by using copy you can make it so only 2 are visible and button-mapped at once.