It sucks that he is leaving New Japan, to be honest. New Japan needs him. WWE and AEW already have more talent than they know what to do with.
And frankly I don't see him moving the needle in AEW or WWE even if he is booked to his maximum potential.
Especially not WWE, what's he going to do more for them than they are already doing? Not like he's going to be moving more tickets for them. Smackdown and NXT TV deals are already wrapped up. If he pops up on Raw, any impact he has isn't going to matter at this point in the Raw TV negotiations.
The AEW audience already by large knows who Okada is, his segments have never did big numbers on TV, so it's not like there is a thirst for Okada from the AEW audience. Maybe it improves some if he's there regularly, but I don't really see it.
TNA could be interesting, he could potentially have a real big impact there but TNA's ceiling is capped way lower than it could be because of them being stuck on AXS.
Just more of the rich get richer. Need a big money international brand to emerge so everyone just doesn't turn into a feeder system to AEW and WWE because those money trains aren't drying up anytime soon unless something devastating happens to the companies or the economies.