Come on man, only Freddie could sing Killer Queen! Paul can't sing it for sure. For me it's one of their best tracks and was one of songs that changed their's careers.
Should they record an album?-Yes!!!
Under Queen name or not?-I think Queen+Paul Rodgers would be good name.
Should John play with them?-Maybe, but if they are still in good relationship, which I suspect, then he should. If they are, that means he's such negative person in this story. But would be interesting to hear his new studio works. He couldn't say any more that tour is hard because studio work is something completely different. Don't know how good songwriters Danny and Jamie are, but I think album would be much better if John could write some songs.
I think I'm banana tree...