The simple delivery of that line is brilliant. Honestly, it has always annoyed me that the companions that were there only really interacted with their Doctor, outside of Tegan getting annoyed at Hurdnall for implying that the women folk make tea and sammies. And I always thought that Susan, if she were a true Gallifreyan, would understand that all the Doctors were her grandfather, not just the old guy. But then, I always read too much into everything.
Again, I think this is just reflecting the time it was made. She was written at a time when young people, especially young women, thought they had a duty to stay close to family if they believed that they were needed. The Doctor is giving her that push to not only instill the courage to move on, but to take any guilt from her in doing so. At least, that was always my interpretation.
:Lovely speech. And not a lie if you take the Big Audio works into consideration. He did go back and visit her (I think McGann did, but I could be mistaken.)
Yeah. That seemed like such a dick move. However, would you rather Jon and Pat ignoring her, or Tennant getting indignant about not coming back, only to end in an uplifting chorus and swelling orchestral, a teary-eyed hug, her reminding him that he's not really alone, and him in the TARDIS, traveling off looking miserable?