They could just make it so it the throws actually track him during his wiggle motion. Throws nor attacks actually hit him with the exception of sweeps like you said @Rikuto. Sometimes i try to throw my friend when he does it because i know of the reward but unfortunately its also unthrowable making the move really good. However i wouldn't say its really broke, just needs that minor tweak of it being actually throwable like any other sidestep move, that alone would fix it IMO.
EDIT: I got you CE
MASTER
Alright, I did list that as an option so let's explore the cons of it for a moment.
Let's assume for a moment that grapplers are actually very viable in DOA 5, and being high-counter thrown is going to result in at least 50% from some of them, maybe closer to death with some of the environmental insanity going on. It could happen, right?
As the game is programmed currently, if Hayate uses the move in the correct direction he will get a backturned stun and all of that guaranteed damage that goes with it if you know what you're doing. Granted right now im terrible with him and can't combo worth a damn, but i imagine there's gota be around a 50% combo from backstun in open space.
So Hayate and Bass are fighting. Hayate rushes in with 66p or something and it's blocked. He free cancels and is at significant disadvantage. He can still use his sidestep move before any of Bass's really dangerous strikes come out though, and it can give him that 50%+ backturned combo if it lands.if Bass anticipates this, he can throw him back for 50%+ as well. If Hayate knows that Bass knows, he goes to layer 3 yomi and uses his most unsafe, highest launching normal strike for high-counter damage, and gets around the same damage at the end of the combo. if Bass goes to layer 4, he'll use something like 6f+k because he is at advantage and it will go into his air throw for similar results. Hayate could then reset this whole thing and go back to layer 1 using his sidestep move.
So basically, the existence of this move means that the entire match can be played in an entirely minimalistic manner with only the moves i listed above. Others could be used, yes, but once Hayate closes the distance after that first 66P, he can effectively set the terms of the match if he chooses to, and it will probably never leave the 4 moves being used that I described above.
If it did, there would have to be something much better, because its hard to get more than 50% on a whim.
So the question is, do you really want matches against hayate going down like that?
Like I said, it would certainly be "balanced" against a grappler... but I'm not sure it would make for great gameplay. It's about as coinflip as it gets, and disadvantage doesn't really effect the situation at all. Both characters have a pretty equal chance of dying instantly here, and it didn't take much planning to make it happen at all.
So while this move is indeed "broken" as it is, I worry a bit about the method used to fix it.