I guess, as a classic Who fan, one has to be pretty tolerant of monsters that look a bit rubbish.

I've talked about Ursula's fate with pretty much all the commenters above. But I take issue with the idea that she is only "existing" and not "living" - there are many people with severe disabilities who would, I think, contest that they are still living even though they are limited in what they can do and experience and would certainly object to the suggestion that they would be better off dead. Ursula and Elton tell us they are happy and I'm quite prepared to accept that.