Aldaron
Luffy is nothing like other DF users. Nothing. His boosts to power are
galactic compared to anything else out there. Look at Lucci's zoan with its measly little stat buffs. Now look at G4 going from Luffy tickling doflamingo to blasting him the fuck hell away like he's nothing. Luffy gets like five times stronger. And these are perpetual "modes" that he goes into and all his attributes shoot up. He moves far faster, his attacks are a gazillion times stronger, he reacts faster, he tanks attacks better. Just like an SSJ mode.
It would not be okay with Luffy using his rubber fruit to give himself a "boost" because Oda is heavily over-relying on the stat multiplication side of things for dramatic effect and that in turn makes Luffy's basic combat abilities absolutely atrocious by proxy. If we are to assume the admirals were using their basic attacks, they undoubtedly look a lot stronger in comparison to Luffy's base stats without the need to enter a form. If Luffy used his abilities more as individual tactical elements in fights, and tied it all together by making fights the same way he used to, the older, more creative, less black-and-white way, we'd be able to keep the core of Luffy while still having him evolve his ability in cool ways and grow in power in a way that isn't overblown and SSJ-esque but still awesome, as long as it's the creativity and interesting power usages you want and not the mindless flash. One does not have to mean the other.
TheFourthChaser
I just want moderation. Balance. Yes the basic techniques getting stronger over time but that doesn't mean changing nothing ever. Exactly what we used to have. Not super mode blitzkrieging the enemy in every. single. fight that matters. Preferably not super mode blitzkrieging the enemy at all because it's generally a boring way of fighting and doesn't even really fit very well in a series like One Piece. The Lucci fight is only as good as it is because of novelty and the sheer amount of emotion packed into it. It is all about the progression of base stats. I am not asking for ridiculous high base stats.
Concrete examples?
G2: don't make it such a
huge boost in the first place. Make the technique effective but moderate in its effect. The boost was too damn big and too vertical, leading to it becoming impossible for Oda to write fights where G2 wasn't the best option all the time. This in turn led to Luffy's base stats starting to look like crap because the enemies had to be able to withstand G2. Now post-timeskip he's nerfed it into oblivion, its symbolic power and meaning lies trampled in the mud and it's all just sad and laughable at the same time. If you made it a more moderate, horizontal power-up in the
first place, while Luffy's base stats
stay strong? This problem will be neatly evaded. It will be a tactical element in a fight, not a superman mode. We could still have the same progression over the timeskip where he learns to selectively apply it and loses the heavy energy drain.
G3: it's good, really. Perhaps it should be slightly faster.
G4: don't make it such a
huge boost. Seriously. Screw the kids who want their flash fix. The concept is fine, it's cool, that's not the issue. The goddamned SSJ esque stat multiplication concept is. It's far too vertical. If it was more horizontal it would have been able to be another cool tactical element that together with the other Gears made a dynamic, adaptable fighting style where the base stats remained respectable. But because the boost is so galactic, it just doesn't.