I've always thought gravity mastery was a bad thing, because it barely captures any gravity related themes. There's the Q which is kinda gravity, because of the pull?
Then there's the gravity effects, but they last for 3 seconds, making changes that are barely noticable.
The problem with reworking the mastery is that a lot of anime fans would get mad that they lose the ability, which is fair, I guess.
That's why I suggest reworking the mastery itself, and have the Gojo ability be a badge ability, just without the low and high gravity effects.
Now, this badge ability would have a new obtainment, BUT so those who already had the mastery doesn't end up feeling cheated, I think you could add ANOTHER BADGE that's called "OG Gravity Mastery", which players automatically get for just having the old gojo gravity mastery. Players with this badge would automatically get the new Gojo badge ability, so they don't feel like they've wasted their effort.
This badge would disabled after the rework, so the new obtainment doesn't get forgotten either.
I think this would be a good way to minimize dissatisfaction across the fanbase if Gravity Mastery is get a rework, because it does need one. Seriously, there's so many cool creative concepts for a gravity related ability, and it could open up for so many different styles of combat, so don't let it go to waste by an anime reference.