Because it has startup, there is counterplay. As in, they can play around it rather than not be able to play around it. There are jump ins he can parry and those that he can’t, on purpose, so that he has to care about which is which and not just beat everything with what would amount to a 1f startup huge dragon punch (on a grappler!) if it could hit back guaranteed in all situations.
Midori’s overall power level seems good right now, and there are many uses of his parry, so it all seems like it’s in a good place. My advice would be to learn when the parry will work and only use it at those times, then use other tools such as neutral A chop, or dragon transform -> A,A, or simply block the other times.