I'm never surprised that MNK is the least played in all content (barring some Ultimates). I'm certain MNK has been the least played DPS job since HW minus a brief moment in SB where it was slightly above MCH. The job's become stale since HW as no interesting mechanic has been introduced. DRG got BotD upkeep which is rewarded with LotD, while not much of a mechanic is at least a gauge that ramps up and allows a decent burst phase. NIN has Ninki management and while not the most intuitive at least has some decent skills attached to it. Ninjutsu feels engaging and is super nice when you can chain Ninjutsu together when out of melee range. I haven't played SAM since SB but my wife has it leveled and even that seems somewhat improved rotationally.

There's nothing engaging about GL or Chakra stacks 6 years (4 for chakras) after their inception. To me personally neither feel like a mechanic, I have no control over chakras and GL is so easy to maintain now that there's no thought needed. If you lose GL it's because 1) The fight forces you too. 2) You died. Or 3) you fell into the trap of using TK when you shouldn't have. Neither 'mechanics' have evolved in the slightest. Keeping GL has been made easier but outside of that there's almost no interaction with the gauge itself. The job is just boring now which pains me to say because I love martial artists in other games because the aesthetics resonate with me. It almost feels like they've palmed all 'engagement' into the same positionals we've been doing for 6 years and given up on any other form of engagement. I think MNK's numbers are as high as they are currently because they're at least still really good DPS wise. Just a shame that after 6 years MNK has had next to 0 evolution.

Rework when please SE?