I'm not sure which bit you're querying, so I'll try to be comprehensive! I don't generally like using the role of companion as a romantic interest because I feel the power imbalance is crippling. You have this much older guy, these generally very young girls, getting shown the whole universe, but utterly dependent on that guy in that context, and generally desperate not to have to leave this glamorous exciting life, and yet, inevitably, because of the format of the show, they will be, and they'll be, well, not literally replaced but...still kind of replaced. Probably with another girl with a crush on the Doctor. That's one of the reasons why I can get on board with Doctor/River - because I feel she isn't dependent on him to maintain her own life in a way of her own choosing.

In Amy's case, I thought it was interesting that Moffat chose to acknowledge the romantic mystique of the Doctor directly by having Amy project that onto him, but have the Doctor not reciprocate and not take on that role of exploitative older guy.

In terms of feeling like the ways in which it was exploitative were explored, I don't specifically mean the romantic elements, which I don't think the Doctor reciprocated, but more, the entire relationship. The fact that his involvement with her life - from childhood onwards - was a big part of the ways in which Amy Pond's psychology is broken. At the end of the fifth season, he goes to his death to save the universe, yes, but in some ways, also to fix what he broke for her. And that's more what I meant. I felt the relationship between them was more complex because it wasn't just a case of him showing up and proving to her that she could Be More and Bringing out the Best in her - it acknowledged more of the ways in which the whole thing wasn't brilliantly healthy, as well as the ways in which it was wonderful.

Am I making sense? *hopes* ;)