The problem with that is that all of the jobs you mention, who have longer duration buffs that basically don't fall off due to their duration, have other systems in place that give them engaging gameplay rather than just upkeeping a buff or two. The Sen/Iaijutsu and Kenki on Samurai are the primary parts that inform Samurai's gameplay, while Shifu and Jinpu contribute toward the Sens in particular (and also provide speed and round out the flow of its skills). Ninja is the same way, it has Huton as a buff to maintain, but its actual gameplay is informed by it's Mudras, Ninki, and the rest of its oGCDs.
Dragoon is a decent comparison to Monk in terms of gameplay but I don't think they share a lot of pains, rather I'd say that Dragoon is an example of how a buff similar to Greased Lightning was built upon in an intelligent and satisfying manner. It's Blood of the Dragon, not Life of the Dragon that's the equivalent to Greased Lightning, while Life of the Dragon is something that Monk lacks that it could sorely use. Both Blood of the Dragon and Greased Lightning are similar in that they're buffs you are incentivized to keep up at all times to do decent damage, Monk through buffing all actions, Dragoon through extended Combos and buffed Jumps. Life of the Dragon however is a reward for proper upkeep of that buff (it's most direct equivalent is actually Foul/Xenoglossy to that end), but that's something Monk just doesn't have at all. So while it is a slower build, it's a slower build for a good reason and it neatly punctuates it's buff and ties into the jobs identity (Spear Knights that Jump on things).
Monk has neither of these things. Other than Greased Lightning, it has forms which only allows its combos to flow differently which after you learn it isn't much more engaging than the standard combo progression of others jobs. It doesn't have an adjacent system you have to work Greased Lightning around in the way that Ninja and Samurai have on top of their own buffs. Nor does it have some reward for upkeeping its buff, in Monks case the buff is the end rather than a means to a greater end like Enochian and BoTD have evolved into. And on top of that they've trimmed so much out of the job from expansion to expansion with the vast majority of additions being either Greased Lightning upkeep (that was bad and we no longer need now that we have a skill that just works) or worse replacements to what we lost, that there's nothing satisfying to us at the moment.
A while ago there was a suggestion I saw to the effect of giving Monk something similar to Sabin's Blitz's from FFVI which would be cool, but probably wouldn't happen outside of an expansion dropping so it's unlikely to happen any time soon when there's need for change right now. At the moment however the job is pretty much primed for the latter, when have Six Sided Star and Tornado Kick both of which are woefully underutilized in our kit (seeing 1 use total in a fight pretty frequently, which is the exact reason they changed Shoha on Samurai). It doesn't solve the problem of Anatman existing when it literally never should have to begin with, or the Fist stances never having the problem they've had since 2.0 fixed while they continue to soak up trait slots making them utterly worthless at the same time, but like the 5.05 changes it would be a step towards something better.
But without Greased Lightning, Monk loses it's identity in this game. That is what defines Monk for better or worse, and I think without it Monk would be even more boring than it is now.