I agree with all that but I still don't think it explains why Scott and Charlie are against it so much. (not that I expect you to explain it) Bon and Brian never sounded the same but even if the AC/DC formula was there they didn't shy away from the songs. There is a number of others who did it as well, including Anthrax and Joey sings some of those songs. I think Scott and Charlie just have their heads up their arses
Fixed that for you
I don't think he does.
But on a more serious note I seem to remember reading somewhere when Joey came back that he was coming back as hired help not as the partner he once might have been and therefore not having a say could be quite true.