Batman is definitely awful MU, his mech bats punish every gap, even J2/leap 2 into anything is punished. Also its easy to AA leaps with Bats nvm batman low hitbox making it already hard to leap on him, also his d2 is exceptional for that reason vs Grodd. Top that with parry and great backdash to escape pressure. Also 6frames d2 is something that makes cancel pressure harder too.
Grodd cannot vortex batman - he is the only character that can escape both throw and mleap 2 by dashing forward
As a large hitbox character Grodd is subject to jailing upbatarangs in pressure strings like b11~mb uprang etc.
Grodd answer to mech.bats? MB stampede and trait. THATS ALL. Most chars have some moves that low profile bats or at least jump through it, but not grodd - his jump is too floaty and his df3 is the only move that profiles bats somehow, but its recovery is too obnoxious and low profiling is too slow to use it reliably, more like a hard read that cost you 30% and deal 7%. Trait is not good vs bats as batman reading your activation can do lots of things from rush in to grapple, where at best you buy yourself some time, but no real way to get anything serious started. Stampede cost bar and you have to once again throw it out at random. Im not saying its bad, but you could as well just use that bar to pushblock - thats guaranteed at least.
I cant see Grodd remotely winning this MU, sorry, he has zero answers to Batman options, where batman has every answer to everything Grodd has, actually multiple answers at that. The only reason Im hesitating to put it as 3-7 is because I've yet to see any batman utilize MU knowledge.
WW isnt remotely as bad as people claim, but still bad. If WW is 3-7 than Aquaman is what, 2-8? WW MU feels bad, but not unwinnable.