Tennant's adorable, don't get me wrong :D And I do LIKE Ten. But Nine was snarky and snarly and at times morally ambiguous, which was fascinating to watch. Ten has high morals but has a very "do as I say, not as I do" policy at times :|
But yeah. Ten is a jerk, and a bit of a child. Tennant makes him likeable regardless xD;

The whole point of the Doctor is to teach us about the thrills and spills about being human from an admiring outsider's perspective. How to be better people in general. To have this idolized and idealized alien to look up to. And I agree! If the adventures are engaging and if he's written well enough where I don't CARE that he's a Stu, who the fuck cares :|

I like Nine/Rose better because they snark xD; I'm a sucker for a good snarky relationship. Ten/Rose is too...purely fluffy at times. Nothing wrong with that, but it's not really to my taste much anymore. Nine/Rose has fluff, but also wit and sarcasm. I LOVED that ♥
...Honestly, the age thing doesn't really make me blink? Because I'm typically more worried about the interaction between characters before the technicalities like that. She's at an age where she's coming to know herself and what she wants, so I'm okay with it. And besides, it's fiction. A big age difference in real life will cause raised eyebrows until I'm sure of the sincerity of the relationship, but it doesn't matter much to me in fiction xD