I'd actually say that going from ARR into Heavensward they introduced mechanics onto other jobs that were basically differently flavored Greased Lightning in Blood of the Dragon, Enochian, and they elevated Huton to that by giving Ninja Armor Crush. In terms of the pressures the jobs were subject to and how strict timers were, BotD, Enochian and Greased Lightning were all fairly similar. Recovery was uneven between them, with Monk having a significantly longer cooldown on Perfect Balance than Enochian or Blood of the Dragon but the ability to slowly rebuild stacks when it was on CD, while a Dragoon or a Black Mage losing their respective buff would be out of luck for until the minute it took for the BotD/Enochian to come off cooldown. Monk still ended up getting the short end of the stick in terms of fight design because being able to recover from losing your buff every 60 seconds gives more flexibility for forced disengages than only being able to recovery at max speed every 3 minutes.
The problem was, moving into Stormblood they alleviated all of those pressures on Black Mage and Dragoon by making their buffs much harder to lose over the course of a rotation. On top of that both Black Mage and Dragoon both gained a means of instantly refreshing those buffs with a button press (Spamming Transpose or hitting BotD again respectively). They also lost their significant penalty for letting it fall off, as Enochian and Blood of the Dragon both had their cooldowns reduced to 30 seconds so if they dropped they wouldn't go more than a few GCDS before they'd get it back. However Monk didn't get that same treatment, it's tool for refreshing Greased Lightning was Riddle of Earth, which was utterly worthless in a ton of situations (including the situation of a Scholar Critting their Adlo because shields block it's activation) or would require some scummy play to activate like taking a hit that would give you a vuln stack. Shadowbringers ended up being more offensive due to the devs being willing to completely eliminate the difficulty of upkeeping buffs that were by all rights direct equivalents to Greased Lightning on other jobs while Monk still hadn't even caught up to buff upkeep levels other jobs had in Stormblood despite receiving a new skill for it (and possibly two from an internal development perspective from how they talked about 6SS in the media tour). And obviously we saw how that went. Anatman's history is well known and Six Sided Star for all that it's useful as a disengage tool was still redundant with other parts of the kit even if it was better so it was always doomed to make people mad.
I'm not convinced this all happened because they wanted Monk to be different. Instead I think it's because they convinced themselves that Monk was already complete and so they utterly failed to implement the lessons they learned on other jobs that had mechanics that nearly directly copied Greased Lightning in development. Had Form Shift refreshed Greased Lightning in 4.0 and Riddle of Earth didn't exist, Monk would have been at parity with Black Mage as far as buff upkeep went and there wouldn't be two expansions worth of excess GL upkeep buttons for people to mad about.
This is also why I feel like the goal of the upcoming rework is just completely missing the mark. They've said that the goal is to eliminate the stress of upkeeping Greased Lightning... but there's no issue with that now. Monk has achieved parity with Black Mage and Dragoon in 5.3 by letting you upkeep it with one button. The problems we have lie elsewhere in the kit. Monk needs an actual recovery skill for Greased Lightning because right now it doesn't have one, Anatman is terrible for building more than one stack and useless otherwise, and they accidentally turned Perfect Balance into a Meikyo Shisui like damage cooldown with Leaden Bootshine. There's too many skills/traits that just do nothing at all like Tornado Kick and the Fist Stances. The lack of new skills we actually get to use rotationally has made people frustrated for two expansions now. Meanwhile there's things the players actively hate like RNG Chakra which should have been fixed but haven't. Greased Lightning is only tangentially related to that. The only reason I can feel somewhat good about the upcoming rework is that turning Greased Lightning into a trait forces them to change most of the things that are actually problems so they might end up fixing some of these problems on accident. It also prevents them from making at least one of the stupid mistakes they made multiple times from happening again by making new skills to refresh Greased Lightning impossible.