I think the title says it all. If in addition to the current setup, we could have a global cross hotbar that shows up when L2 and R2 are pressed down, that would be a welcome addition, for a number of uses. I would personally use it to have all my buffs and anything situational. Currently, unless you're using toggle mode, tapping R1 to switch is slow because I have to release the R2/L2 buttons and repress them to see the change. I do use /chotbar change macros, but that's still a pain.

In short, L2 + R2 = Cross Hotbar 9.