To be fair MNK has a current PVE setup where it has multiple branches so there is choice involved (if you ignore 100% optimization anyway, like I know mathematically there is only 1 best way but most players cannot achieve this).
PVE MNK:
Dragon Kick > Twin Snakes > Snap Punch
Dragon Kick > True Strike > Snap Punch
Dragon Kick > True Strike > Demolish
Dragon Kick > Twin Snakes > Demolish
Boot Shine > True Strike > Demolish
Boot Shine > Twin Snakes > Demolish
Boot Shine > Twin Snakes > Snap Punch
Boot Shine > True Strike > Snap Punch
PVP MNK:
Boot Shine > True Strike > Snap Punch
Dragon Kick > Twin Snakes > Demolish
Obvious difference is obvious. One of these modes has way more choices and options. Which is why making this an optional thing would likely not work since it would likely cause imbalance.
SAM would have the same problem since it has 3 combos that branch off of Hakaze, if you notice for PVP they simply removed Hakaze. Removing abilities in order to make this system work is dumbing it down in my opinion.
