I was actually having trouble with this when I maxed out the pld class.
I use a controller with a setup that effectively gives me 32 buttons without having to manually swap to another crossbar and it's still not enough.
I've tried to limit the cross role abilities to stuff I might actually use in any given scenario including dropping low kick in favor of just opting for shield bash, but there's only so much fat you can cut before you're left with either dropping essential skills or being forced to manually swap crossbars mid combat.

It's unbelievable that they still haven't merged shield oath and sword oath into one button.