Flicker is not broken, and I think you know it.
Masteries like Earth,Lightning,Water,Fire,WM (both path), Bubble barely benefits from it if not at all. That is a fact that you will never be able to deny, this brings my point where FLICKER itself is not broken since only a minority of masteries benefits from it... wich yes becomes tilting overtime because it's the meta.
As far as GF and Tai combos, they're annoying but you can combo them mid combo since they knockback and does not stun. It is annoying to play against but there is some kind of counterplay.
Now the main problem is INT WIND users benefitting from a STR WIND Jutsu (Tornadoes , that only requires 20str) that stuns and allows them to deal around 500-600 damage off flicker with 100 int only.
INT MED is also a problem since it's a free stun with only 4sec CD, when in my opinion it should not, changing its hitbox and take off the stun would help, changing the effect would also be a nice thing.
The game is balanced around the basic jutsus, not the other way around and instead of being so stubborn you should accept it. Changing one of them would affect the whole balance since EVERYONE has access to it. You think it would be more easier but it might make things even more complicated later on.