I run Task / Dorm / Doom and I’m NOT an expert with BBF but here’s how I look at the problem with Wolvie and Akuma Assist:
Berserker Slash can’t realistically be blocked on reaction (assuming the Wolvie user knows how to space properly) which would be fine if it wasn’t basically invulnerable because then you just use a fast, forward moving attack to counter it or move to a safe position. I can sometimes beat out a naked B.Slash with Shield Skills (I run Task on point) because the Tail of the Hitbox will actually catch Wolvie or make it a neutral position because Task is moving forward or throw because there is a window between when Wolvie stops moving and before the slash hits when he can be attacked but the timing is so tight it’s not realistic and I’ll only attempt any of these if I’m desperate. The only option really left after the said ones is to slam back then forward (which becomes back once the mix-up finishes) and pray block stun saves you which works about 60% (not much better than random guessing) of the time for me.
Technically, a meter needs to be spent on successful contact of B.Slash to make a combo out of it or make it safe, but when an assist (mainly Akuma Tatsu) can be used to get around that requirement, it almost feels broken because it is nearly the ultimate attack. Both offensive characters are pretty much invulnerable during the attack, have very fast start-ups and it’s near impossible to react against. Plus it comes out faster than any other cross-up in the game which is why I think most people have a problem with it. I don’t know of any “unblockable” setup that is faster than B.Slash and Akuma Tatsu coupled with the fact that works in the corner and you have a mixup that can’t be avoid even while turtling in the corner.
Also the combo gets around nearly all defensive counter measures and pretty much forces the opponent into the corner if they keep backing up (which is what the Wolvie player wants) or forces you to super jump for life (which means you’ll eventually hit the ground and be mixed up). Look at how dominant that combination is:
a) Dorm’s Fire Carpet get’s blown up (Wolvie can travel through it with B.Slash and Akuma Assist Tatsu blows it up about 80% of the time depending on where it gets started from). The Fire Carpet can stop (or at least slowdown) nearly any rush down in the game
b) All low priority projectiles (which are basically all the fast ones) are beat out by Tatsu and Wolvie goes right through them
c) Advancing Guard is bypassed if the assist hits first
d) Random projectile hypers will catch Akuma, but Wolvie just gets behind and hits you out of it
e) Counter hypers are very risky to use because assist can hit first and then you’re still dead
At least in my opinion it seems like the if the only realistic defense against a setup is using even faster rush down (which may be some sort of Felicia / Akuma combo? Wild guess on that one) then it may need to be re-evaluated slightly. If the start-up of B.Slash was increased and was longer or shorter based on the type of slash I don’t think people would have as much of problem because then you could at least see it coming (much like a C.Viper Focus Attack combined with pin down assist) and then have a chance to react with blocking.