We might actually get J transforming for once (since that's likely part of the final battle, so he'd probably arrive standard sized), rather than just big or just small, so he could get some lines, even with replacement VA.
They got J's actor back for Kyoryuger vs Go-busters...
They can probably bring him back to play J again. But I dunno if J is popular enough to be a main character in these movies.
Yuuta Mochizuki actually fell seriously ill a while ago (he had to cancel his appearance at Lexington Comic Con because of it), so unless he already recorded his lines then I don't think he could be involved even if he were asked.
I don't think J being a part of the final battle will change anything.
IIRC, J was already big when he first showed up during All Riders vs Dai Shocker's climax.
And Diend standing on top of J's shoulder like some kind of mech didn't help either :laugh:
And I know J isn't that popular or well liked, but it irks me a bit at how degraded his character is in these kinds of movies compared to the others.
