Max 4 stacks of GL, each worth and only worth 5% Attack Speed. I could dig it.
The conditions for gaining GL could use some clarity, though. I don't really get the point of changing it from just being applied on any Coeurl skill, except perhaps to nerf Perfect Balance. The same goes for GL acquisition "neither grant[ing] the full Greased Lightning stack duration, nor refresh[ing] the duration to the full duration." Given that, I don't know what is meant by a duration "up to a maximum of 60 seconds."
___________________________________
To avoid simply copy-pasting some of my older ideas (including the only-one-stack-falls-at-a-time concept, haha), let me try out a new concept that might sound technical beneath the hood but should seem pretty intuitive on the surface.
GL will function a bit like a much more granular version of HW-era Blood of the Dragon. It would be a spendable resource which also drains over time and is generated from any and all relative potency dealt, exempting the effects of GL itself and any enemy mitigation. That form of generation is a new idea, sure, but ultimately pretty simple -- deal damage, get GL.
The GL tiers are still there, each granting 5% modifiers to your Damage, Defense, and Speed stats (yes, that includes Magic Defense, Ability Recast Speeds, and Movement Speed), to a total of 20%. Exceed the requisite GL Gauge and that's it, you're in the next tier. And if you drop below its requirements, there's a 2.5-second grace period before you actually lose that tier's benefits. (This should allow for you to spend tightly without the average Monk feeling like they have to be incredibly precise... even while it may let highly skilled Monks purposely dip below just before a strong GCD that'd pop them back over.)
But, by the same amount as GL increases your stats, it increases your drain rate, i.e., by 15% per tier, to a total of 60%. It's worth noting by then that at GL4 you're also generating 20% more potency over time (due to increased attack rate), though, so it isn't quite as scary as it may sound. In practice, this really just means that your GL falls off one stack at a time and each lower stack lasts longer than the one before.
So thus far we have something for which our excess can be spent, making it an actual resource rather than just a ramp-up penalty and light maintenance challenge.Simple enough?Graphically, it looks like a horizontal gauge from GL0 with the GL1 threshold marked about two-thirds of the way left-to-right. Once you hit GL1, that progress squishes that down and left and the next threshold is revealed, again two thirds of the way down. Repeat. Repeat. By the end, you have a GL4 gauge with successively smaller and thinner threshold bars as you move from GL4 at two-thirds of the way left-to-right to the previous ones. This means your max banking margin is a third of the total gauge or half of what you've spent just to reach GL4, which is pretty sizeable. (And yes, if you lose a GL tier, the gauge expands/stretches back to how it was at that prior tier.)
____________________________
But, that still leaves us with our potential spenders and GL's other potential interactions. Let's begin with the latter.
I'm not a fan of how only a third of Monk's skills can be used at a time outside of Perfect Balance, so I figure I'd do something about that.
One possibility is to get rid of the openness from Perfect Balance and use dynamic buttons based on stance, such that we more deliberately switch between them, with each stance having, say, 4 options. For instance, Coeurl might have one option that remains in Couerl (modifying that skill itself), two that go to Opo-Opo, and one that goes to Raptor, while Raptor would have one that stays in Raptor (modifying that skill itself), two that go to Couerl, one that goes to Opo-Opo, and so on.
The other obvious option is to simply remove the form limitations altogether. In their place, we could, say, simply have all Form-based weaponskills generate 100% (after acquiring GL4, lower previously) more GL for each preceding unique form different from their own. If I use a Coeurl skill after having used a Raptor and an Opo-opo skill (between that Coeurl skill and the previous one), then that skill generates three time the GL. If I had just one of the two between it and the Coeurl skill -- only double. Back to back Coeurl skills -- only the normal amount. Or, inversely, I get full contribution when I rotate, on average, in even thirds; two-thirds contribution (not sustainable) when I rotate only, on average, between two of the three forms; and only a third of the possible contribution (causing GL to plummet rapidly) when using the same form. It's worth noting that Dragon Kick has been returned to its earlier form (+10% damage to the target) rather than a trigger for Leaden Fist, so it's not worth abusing this freedom to exploit. Like Twin Snakes, you'd want to be minimizing its portion of casts while retaining effective coverage.
Naturally, Perfect Balance would ignore this penalty. However, as mentioned before, I'd rather Monk feel more free-flowing and driven by interactions between its CDs and rotations, rather than those CDs seeming to be the be all and end all of its macro-rotation. On that note, Perfect Balance is now an Additional Effect, generated by a few other, more frequent abilities, and works to nullify the loss of one such skipped step (i.e., returns a +1x multiplier you'd otherwise lose). Just from natural CD usage, you'd be looking at 4 or 5 stacks per minute, which is enough to allow for some no-cost craftiness with your rotations.
So now we're down to the question of spenders.
On what, if not for rotational variance, ought one spend their excess GL? I'll leave that mostly to your imagination, but off the top of my head... (A) actually fun and impactful stances (similar to what I mentioned before, but running off GL, if we're not permitted to use Mana) and/or (B) Tornado Kick, The Forbidden Chakra, and Enlightenment or (C) a way to "rush" out CDs (assuming equal ppm). (The last would certainly fit the idea of Monks being highly adaptable and modular, such as by being able to cycle two normally minute-long CDs into a single 1-minute period, for instance.)
I see no reason to restrict the last two to RNG when we've got a gauge right there into which they'd have more interaction and potential nuance compared to the mere "hit when full" gameplay they have via Chakra. Drop the Chakra entirely unless it's going to have an effect that's actually fun, unique and reminiscent of a theme one might expect from the idea of chakra. Tornado Kick, thereafter, will be your all-spender (like Flare, but with damage nearly proportionate to resource consumed, though technically best to be used just after having dipped below GL4 anyways), thereby remaining your pre-jump or execute skill, essentially precisely redeeming what potency you lost in ramping up (and thus removing any so-called "weakness" to GL in a fight lasting more than some 10 seconds, so long as you can get the kick off before combat ends).