Deep down, I would like to see X Japan continue without Yoshiki (at least for a little while longer to at least see them again one last time). I'll have the opposing opinion & say that Shinya from Dir en grey would be a fine ADDITION (as in adding to the band, NOT replacing Yoshiki or anybody) to the band or even as a session/tour drummer. I've said this once & I'll say it again, I feel that Shinya can keep up with Yoshiki's drumming style & would be fine as a temp.
But lets be real here, session players for things such as this, it's kinda like putting a band-aid over a gunshot wound. If it comes down to it & if Yoshiki can't play drums or do anything anymore, then it would be best to dissolve the band permanently. Like, no BS, make your peace, shut it down & call it a day.
I can you imagine though, living with the thought that you could've done more with your time. The guilt of letting your legions of fans down because of something you couldn't quite control. This is a scary thought. . . I wouldn't be surprised if Yoshiki or ToshI fell into another deep depression if this were to happen. Hell, I'm getting upset just for thinking of the potential impact this could have on him & the rest of the band. Empathy sucks sometimes, my god.