In the new series (2005-present) there have been precisely two (2) acceptable companion leaving scenes. Hint: one of them left with Rory. A lot of the problem seems to stem from the fact that Russell T. Davies clearly believes that The Doctor is So Awesome that the only way that anyone would possibly leave him is if they were violently ripped away from him and had no choice in the matter. So we end up with the huge build-up to Rose's departure, (Will she die? Why will she leave? What's going to happen?) and what we end up getting is Rose having her future decided for her entirely by the various men in her life with absolutely no say or consideration given to what she might choose for herself. At the risk of being serious for a moment, this is the message that's presented through Rose's Departure - just wait for a nice man to come along and make your decisions for you, what you want isn't relevant, Sweetie. Which is absolutely reprehensible. Particularly coming from someone who clearly believes he's writing on overall narrative that's empowering to young women. We come across nearly the exact same situation when Donna leaves. Again we've had several stories in a row featuring the now standard 'I'm never going to leave you, we're going to be together forever!' conversation. Then something tragic happens and it's up to The Doctor to make all the decisions about his funny girl companion's future, because obviously you can't leave something that important up to
her. The counter-argument here (at least as far as Donna is concerned) is, 'he didn't really have a choice, he had to do it, she was dying, etc.' Yes, she was dying. That doesn't change the point. It was not his decision to make, it was hers and he stole it from her. Worse, in the process he stole everything she had learned and experienced. If that was the price to be paid for continuing to live, the choice needed to be hers. Indeed, dramatically that would have been an incredible scene; her having to make the choice between dying as the woman she's become or living as who she was before. That's the scene we should have had to say goodbye to Donna. It's unfortunate that a series which has spent so much time and effort attempting to be empowering to young women has so frequently undone all of that effort in the home stretch.