shark_hat | WELL THAT WAS DISAPPOINTING

God. I mean, leave Rose aside; that can be a happy ending or not for her, as she and Alt-Doctor make it (I am VERY not convinced, but it could happen.) And leave the Doctor; he's coped with being alone a few times now, he'll move on.
But Donna! That was cruel and pointless- why not make the ebbing of the meld traumatic so she chooses to go home? Or that, ooh, say, Tardis energy would reactivate Timelordbrain and kill her so she has to leave- which would have given lots of scope for tearjerking, but not take away all the character development. That'd leave room for a return appearance, too (and if Tate doesn't want to, then she doesn't have to.)
And Alt-Doctor.... God. Rusty created him entirely to a) keep the Doctor's hands clean and b) reward Speshul Magic Companion, and as a result he now has, what, 60 years? of life, TARDIS-less (remember how trapped Three felt?) and with a girl who hankers after another version of him. I think he's got an actual tragic fate, and Emo Doctor doing sadface at the end is a distraction from that. (Regeneration!energy!hand+Donna+handwaving could have done everything Alt-Doctor did, except then Rose would have had to bloody well cope on her own, Oh Noes. [1] Oh all right, and there was quite a big cool factor. And I suppose it was another way of playing with the "He's all alone!" "No he isn't!" "Yes he is, hahaha!" running theme. But then I think that's a bit icky.)
And the "Rose will heal you" thing? Please. That Rose was an ingenue, and this one is rageous and kills Daleks without blinking- which isn't a bad thing, but it's a completely different dynamic.
I hope Alt-Doctor manages to join alt-Unit, pull a few strings and at least get into the spaceship programme. (I also hope that the sensible Donna-ness stays with him.) Poor guy.

[1]I'm cross this episode made me go "Pteh! Rosy Sue!" more. I liked her at the beginning, before she started warping the 'verse around her.

Still, there are many ways it could have been worse. Lots of nice small touches. (Did like the moment of realization and "ick!" about what the heartbeat meant. That's Jossed a lot of speculation about his origins, eh? And Jack-Mickey cameraderie. And stuff.) And next year's Torchwood should be interesting. But...