Catherine Tate's hot... But then attractiveness is subjective. I know plenty of people who find Matt Smith and David Tennant hot, but I know plenty of people who don't. Neither of them is Tom Cruise, or what you would term classically handsome, and let's face it neither is Eccleston. And we have no evidence that the modern day variant of Clara is going to fancy the Doctor. As for Amy, that was a unique circumstance I think. The Doctor was imprinted on her as some kind of magical heroic figure at such an early age that I don't think his looks would have mattered a jot. I don't want to see every companion drooling over the Doctor either, as it happens, but nor would I want to see us go back to a time when it was never even counternanced. Emma Watson, I don't get that either. She's very pretty but beyond that? I'd agree, Emma Thompson is more the kind of actress you'd want if you went down the route of a female Doctor.
Nothing wrong with Tate's appearane, it's just her "Poor people talk so funny LOL" brand of comedy that irritates me. See also, Little Britain. Hottest companions are Clara and Romana I for me.