Honestly I think the biggest problem would be Stinson. IIRC Stinson gave Bucket a hard time when he was in the band, and I get the feeling that if Bucket returned, Stinson would have to go. That would create a serious problem, since although there's a perception that any mug could play the bass ("Just ask Duff back!"), Stinson is the guy who organises all the ground-level band stuff like rehearsals.

Frank would probably get the boot too, in favour of Brain (didn't Bucket make it a requirement of his initial hiring that Brain came on board?). So with Bumble, Frank and Stinson out, that would mean a fundamental reconfiguring of the band. Honestly, with all those comings and goings, I wouldn't be surprised if Fortus threw in the towel at that point.

So yes, it's massively unlikely that Bucket would return. Ironically, the one person who I suspect wouldn't cause any problems is Ashba; he and Bucket have mutual interests (horror films and spooky stuff!), they both seem to connect with Axl on a personal level, and what with Ashba being part of an anti-bullying charity I doubt he'd have time for the shenanigans that allegedly drove Bucket out of the band in the first place.

And half of Ashba's Chinese Democracy live solos are Buckethead ones anyway (Sorry, If The World); between the Bumblefoot shred stuff that Bucket would naturally take on, and the Chinese Democracy solos that he originally recorded, I don't think he'd be standing around as much as in 2002.

Who gives a tuppenny fuck about their opinion?

Of course, were Ron to leave, it'd open the door for Buckethead to return. And much as I love Ron, I'd be intrigued to hear what a Buckethead/Ashba combo would sound like, particularly given their mutual interest in horror films and whatnot.

On a serious note, I'd love to hear them duet together. Billy's breathy vocals plus Axl's rock screech would be interesting to hear.