Its breaks block instantly and can change direction mid air.
Almost all jaks just continuously air camp and spam it to prevent confirms and throws.
I will admit it that this shouldn't be a nerf but the move is just unbalanced. Jack has enough mobility, he isn't meant to be played like a helicopter
Being a helicopter is honestly all Jak has going for him at the moment, keeping him alive long enough to scrounge AP, it takes a fair amount of time to fully charge to guard break power, it also gives him this little midair float that lets you know that he's getting ready. Should he ever get his long awaited buff I could see that it may need to be toned down. But as of now it's his bread and butter, the only reliable move that lets him link into other moves.
If he fires it off he can't use it again until he lands, use that information to fake him out with an air dodge and hit him from underneath, or depending on your character you can just fire a projectile and knock him out of it.