It's just a way-out whacky theory, but I have an idea if they ever did reform, Moz would look after the lyrics, and Marr would deal with the music. I know it's a controversial opinion, but f*** it.
On the other hand, they could offer each other valuable fashion tips. Moz could suggest that maybe Johnny could lay off the hair dye and go grey naturally, whilst Johnny might suggest Moz lay off the gaudy 70's style big collar/ruffled shirts that make him look like a Las Vegas pimp, and that baggy grey sweatpants large enough to could comfortably fit three people inside really don't do him any favours. He might also tell him to f*** off when Moz says he'll only play live if Johnny and the session drummer replacing Mike Joyce have to wear matching 'WE HATES BECKHAM MORE THAN CANCER' T-shirts whilst Andy Rourke dresses in drag.
Yeah, let's face it. That reunion wouldn't go well, would it?