So the speccy-spoiler is that the Doctor, instead of actually regenerating into a different Doctor regenerates into TWO of the same Doctor (I know, two Tennants for the price of one!! Can the world handle so much sexy?!). Some spec has it that one of the Doctors has only one heartbeat and is essentially human, perhaps regenerating the non-Time Lord portion of the Doctor. And thus, Rose and the Doctor get a happy ending, because THAT Doctor and Rose can then go off to Pete's World and live happily ever after.
I'm okay with that, I guess, with all things considered in the pragmatic reality that we could simply get a happy ending no other way on this show. Well, I'm happy with it on a couple of conditions:
1. That it's clear that while he won't be time-space-traveling Doctor -- obviously not possible without the TARDIS, though how awesome would another TARDIS be which would allow the Doctor and Rose to do in Pete's World (Universe) what the Doctor does in this universe ... anyhoo, back to my point. That it's clear that while he won't be time-space-traveling Doctor, he'll still be THE Doctor and do Doctor-like stuff, but ... I don't even know if that would be possible without the TARDIS and Time-Lord aspect. Sigh.
2. That the other Doctor doesn't just forget Rose, but rather that he erases his own memories or whatever. I want the Doctor's love for Rose to not just be a part of him, but to be woven through all of him, and not just the non-Time-Lord part of him. Having another Doctor happy with Rose would be (a) too painful and yet (b) too fantastic for the Doctor WITHOUT Rose to contemplate, thus he erases those memories and/or feelings. That way, the show can carry on with the Doctor doing his thing, without being all owoeismemylostloveROSE!, and we can just carry on with the show, the Doctor moving on easily and completely without it being a betrayal of any kind of their great love story. And, damnit, theirs IS a great love story. (Plus, it would allow shippers everywhere to not want to string Moffat up by his fingernails when he, no doubt, ignores all of the Doctor-loves-Rose canon.)
I don't know. On one hand, it really would be the only way to provide a happy ending, but, but, but the Doctor without the TARDIS, without being a Time Lord is a part of why Rose fell in love with him, and why the Doctor fell for her -- because she got that he was a Time Lord, appreciated that, but loved the man, and her love of the traveling, adventure, saving the universe, etc.
So, yeah, I don't know. A whole other week to wait, huh? Yeah, this is gonna be torture. Plain and simple. Sigh.
ETA an excited thought, ... it is that the Doctor goes with Rose and the other stays here, and like afrocurlmentioned below he does Doctor-like stuff like the 3rd Doctor did and then, then they could have an episode lite for whoever the companion is in s5 and just show Doctor and Rose in the AU. Just a little treat. Whoah, getting waaaaaaaaaaaaay ahead of myself, LOL!