Buckethead was brought in when Robin left. Robin was Axl's initial choice and he is still there, so I think they are gonna be fine. Fortus is equally as capable. Hell, Buckethead didn't really have that big of a role in the shows that I saw, except for his solos. I don't think that he was in any way the heart of the new Guns.
I wondered how long he would last. I think Finck is a better fit anyway, although I did like Bucketheads playing, I think that Guns will survive without him.
Axl is trying to make these guys into Guns N' Roses. He wants it to be a band, and it seems to working for the most part, seeing as no one has left except Bucket. I think if any one signed up not thinking it would be a long haul,especially some of the newer guys, then they were crazy.