In all honestly a Fisticuffs tweak was warranted and I expected something. It was fairly busted in certain matchups. Not unbeatable, but definitely silly. But just adding 5 frames to the move wasn't the way to fix everything. I was genuinely surprised when the patch notes showed just a nerf (which was wrong about the frame change) and no other buffs or fixes. The nerf hurt him more than it seemed since the main reason to use Fisticuffs overall was the fact that he had a 9 frame mid, which was the fastest of any Cage variation. I felt that this was a fair trade since Fisticuffs doesn't get the same use out of F3 that the other variations do. Now it is 11 frames which is the speed of F3 so it doesn't fill that spot anymore.
Another thing that hurts Fisticuffs is the fact that block hitboxes/pushback is variable. This means that you could the same thing on repeat and a different amount of b121 hits will connect on block on the same opponent. Sometimes on block you may get 4 hits then whiff, sometimes 6 then whiff, or get 4 hits, whiff the 5th, then hit the 6th and whiff the rest. Think similarly to the problem Brady has been having with Ex Ice Clone. Where sometimes it would be too close and sometimes not, even when doing the same exact thing on repeat.
Every character in the game has about 4 or so different block animations that they rotate between, but it is random which one is used on any given hit. I think that this may have something to do with the varying hurtbox locations. I have noticed that if certain block animations come up then b121 gets pushed out quicker. It is very strange. However it may just be coincidence and the cause of this may just be "breathing hurtboxes", or some combination of multiple things(or I may just be over thinking everything and looking for answers where there are none). Either way it is likely impossible to fix and is frustrating to deal with since you can't plan or account for it.