Monk is really the only job you couldn't condense combos into singular buttons for due to how everything on it works with the different Forms and the Blitz system.

While simplifying the gameplay would be an effect of it, it would also help with some of the dreaded button bloat.

Aside from the combos, some other things on various Jobs that could be done for that also exist as well...

BLM, Fire 4 and Blizzard 4 can only be used with Astral Fire and Umbral Ice respectively, so they might as well be under 1 button. Same with Freeze and Flare. And Between The Lines could easily be moved to replace Ley Lines while they're active.

DRG, Wheeling Thrust and Fang and Claw being only usable with their respective buffs could be just 1 button and not 2. Or just worked into 1 button combo buttons.

SAM, Tsubame-gaeshi could probably be worked into the Iaijutsu button. Ikishoten and Ogi Namikiri probably could also just be one button.