I'll be honest. I think I would've enjoyed that version of the game, depending on what was missing. It would've been annoying if they took out the portals, but it could have been more humorous if they used the early model of the Portal gun -- You know, that Ghostbuster-like tube with a backpack that you see on some of the safety posters around The Fall chapter. And an aging and desperate Cave Johnson wouldn't have been the worst villain. During the early chapters of P2 I became really tired and annoyed with GLaDOS' shtick, but Cave Johnson's pre-recorded public service announcements were a refreshing and hilarious change.
I also thought it was wierd that Chell was put back in Aperture Science instead of using a completely different test subject for this sequel. She (with your help) earned her freedom, and ApSci has a very blatant record of keeping extra test subjects on hand. Yes, they've made it pretty clear in this version of P2 that she was the only human test subject left alive, but that could've gone in a completely different direction. Didn't Rattman move her to the top of the test list, anyway? (Speaking of Rattman, where the heck is he?!)
I still think they could go that route in a future installment of the game. In fact, after beating Portal 2's single player campaign, I'm really hoping they do.