Not a big Genesis fan, but I think Michael's theory is wrong.
If I were to guess, if these five got together, it wouldn't sound like old Genesis at all. Think of the proggy side of 80s Genesis, the esoteric side Peter Gabriel's solo stuff, and the latest Hackett stuff - put in a blender and hit frappe. You Collins will just sit behind the kit? No way. Phil and Peter will split the vocal duties on the hypothetical album, and the hypothetical tour will include PG-Genesis and PC-Genesis tunes. Imagine "Tonight, Tonight, Tonight" with the bridge expanded into a longer jam featuring flute stuff by Gabe. Picture "Games Without Frontiers" performed by the whole Genesis band. Think of a medley of Gabe, Collins, and Hackett solo work mixed together.
But if I had to guess, the album these five would make would sound NOTHING like old Genesis. It'd be good, but totally different.
Again, this is from a person whose opinion of Genesis is best summarized in one syllable:
"meh"
