2. The Time Lords In "End Of Time"
There are huge flaws with the final Tennant adventure (for one, all the buildup about Donna's brain exploding if she retained any memories of her time with the Doctor, which is quickly dropped and forgotten about), but the most egregious one for me is the way the Time Lords, one of the most legendary and powerful races in the universe, are finally reintroduced to the series. They only spend about five minutes total on screen before they are quickly shuffled away again into whatever corner of the space-time continuum they had been safely locked into. And what was with the mysterious looks that female Time Lord was giving the Doctor? And who was she, anyway? Susan? Romana? The Doctor's mother? That's apparently not a question this episode is interested in answering, as the Time Lords are quickly forgotten about. This is in order to bring about the tremendously self-indulgent twenty minute long farewell tour the Doctor embarks upon after realizing his impending demise. Why on Earth bring Rasillon and the Time Lords back at all if you're barely going to use them? When they initially appeared in the series at the end of "The War Games" they were terrifying mysterious, all-powerful beings that appeared from nowhere and forced the Doctor to regenerate. Here, they're merely some aloof looking dudes in robes who sit in chairs looking pompous. Kind of sad, really.