I loved this as I was watching it but, in retrospect things come to the fore which, while not making it bad in anyway, stop it being a really great episode of Doctor Who.
One of the main things preventing this being a really great episode of Doctor Who is, paradoxically, one of the reasons I enjoyed it so much. This episode was talking to the fans. Most of the episode was tied up in pushing fannish buttons: addressing issues like the Doctor's loneliness, his family, even the whole debate about whether the sonic screwdriver is a weapon. None of which, especially as dealt with here, carries much actual weight outside of the specific context of Doctor Who in 2008. So far every episode this season as been "fan-pleasing" in some sense, whether addressing fannish debates (The Doctor's Daughter, The Fires of Pompeii), revisiting past companions or old monsters (Partners in Crime, Planet of the Ood, The Sontaran Strategem/The Poison Sky) or even constructed to be reminiscent of old school Doctor Who (The Sontarain Strategem/The Poison Sky again I would say). I'm enjoying it a great deal but I do wonder what the cause is. Is there a recognition that the huge popularity of New Who has peaked and it now needs to consolidate and play more to its core audience or has Russell T. Davies forgotten his own advice about not listening to fans and the worst excesses of 1980s Doctor Who?
I very much liked the character of Jenny and thought Georgia Moffett was good in the role*. She's been widely compared to Buffy, which I don't quite see. OK, so she is blond and can do back-flips but there was none of the "valley-girl meets action heroine" concept about her, relatively little angst (on her part anyway) and an emphasis on guns rather than kung-fu wire work. I suppose you could note that she is a female weapon constructed by the patriarchy with, initially, little concept of having any agency of her own but I'm not sure that equates to being a Buffy clone even if you try to shoe-horn the Doctor into a Giles role. I liked the way the three characters of the Doctor, Donna and Jenny interacted with both the women challenging the Doctor in different ways. I thought it was a shame though that the Doctor never answered Jenny's challenges about his soldierly nature and his use of the sonic screwdriver as a weapon. I realise there isn't a good sound-bite answer to this but if the show wants to discuss the issues then it needs some idea of where it stands on the debate. It seems to be reaching for something with the Doctor's distaste for guns and direct killing in both this episode and the previous ones but I don't think its really satisfactorarily grasped the nettle and started exploring the problem properly, especially since the Doctor was effectively proved wrong by UNIT last week.
iriswildthyme suggested (over on JadePagodaTV) that the moment where UNIT stood up to the Doctor might be a key thematic moment for the season which I rejected then, but in the light of the same debate being raised and not really resolved this week I wonder if he had a point.
Martha had a use, thankfully, although she was still side-lined a bit. The moment she fell down a cliff was a little naff and reminded me of Sarah Jane "falling" down a so-called "cliff" in The Five Doctors - but at least it was actually a slope and we didn't have to suffer Freema Agyeman trying to generate tension while rolling across some perfectly level grass. Clearly Donna was needed to mediate between the Doctor and Jenny, so Martha got to show us the Hath side of the conflict. Donna worked better this week, than last, when despite people's praise of her I felt she was actually side-lined rather. That said, I didn't think the "I was a secretary" bit worked so well as in The Sontaran Strategem; it felt a little artificial and forced to me.
Lastly, aside from all the fannish bits, and I'd say nearly all the above were fannish bits. I liked the idea of the multiple-generation seven-day war. This is the sort of idea we've seen relatively little of in Doctor Who since Hartnell's days. I think there were problems with its execution, mostly because the episode was more interested in the Doctor and Jenny. However, Time and Relative Dissertations in Space had an interesting essay on the way old style Doctor Who drew on a theatrical tradition to provide world-building through language and that wasn't really happening here. The details of the world, the Hath, the colonists and the General Cobb's background were never provided leaving them at the level of a simplistic morality play enacted by ciphers. This was a shame but I still applaud the fact they tried to fit a big idea in there.
Lastly a few fan nitpicks and questions for fan-targetted episode: I see the TARDIS translation circuits are on the blink again, a shame because it would have been nice to hear the Hath speak for themselves. The whole regeneration sequence raises a lot of interesting questions (why did the Doctor say she was "too like him"? why didn't her appearance change?). I know the official line continues to stress that David Tennant will continue in the role beyond the end of the season, but this odd remark along with the Ood prophesy about the end of his song make me wonder if we're building up to some sort of "Doctor dies" climax to the season.
*I had been concerned this was entirely stunt casting. Let's cast Peter Davison's daughter as the Doctor's daughter and guarantee a few headlines. A particular scary facet of this is that I remember the announcement of her birth. I've been a Dr Who fan longer than she has been alive!
EDIT: Reading Simon Forward's blog reminded me that I really wanted Jenny to be Susan's Mum or Aunty not a clone. I was still happy but I'd have been happier if she'd been someone with a past history with the Doctor.