Yeah, I don't get why people are worried that she'll be the next companion. Moffat went out of his way to comment on how much younger the Doctor looked, which seemed to me to be a shout out to fandom that they didn't need to worry about her being the Companion in season 5.

I love the idea that this meeting actually causes they're eventual relationship because I can see the Doctor avoiding her for a century or two out of sheer bloody-mindedness, but then his curiosity will get the better of him and he'll pop in to visit her and find her kind of interesting and then he'll leave and then he'll wonder so he'll come back to see if he missed something and the cycle will repeat till eventually they fall in love and get married.