Roger, from what I understand Stephen Moffat (the new lead writer for the 2010 series) intended to bring back River Song and tell the story of her relationship with the Doctor, but then once David Tennant announced he was leaving those scripts had to be scrapped. Fandom is pretty divided on River Song, and those of us who couldn't stand the character weren't too disappointed
Tank, this surprises me:
Except for an implied but unrealilzed attraction between Billie Piper's Rose and this last Doctor
It was made pretty explicit, actually. The love/attraction was implied with the Ninth Doctor, but then Rose actually told the Doctor she loved him in
Doomsday and, though he never said it back, it was strongly implied twice that he would have except that he doesn't say that sort of thing
He then pined for her all through the third season and was overjoyed to get her back. Rose's final scene - kissing the duplicate Doctor - made the romance pretty clear. Writers, producers and actors, in interviews and behind-the-scenes documentaries, have all described the Doctor/Rose relationship as a romance and a love story.
In New Who, too, the Doctor's far more of a sexual creature than ever before, though admittedly that started with the Eighth Doctor movie. Nine flirted with just about every attractive woman, and even one man, who crossed his path, and kissed Rose (and Jack). Ten kissed Rose, Reinette, Martha, Astrid and Donna, and it's very strongly implied that he slept with Reinette. With Moffat taking over - the writer who, more than anyone, has tended to write the Doctor as an intergalactic Casanova (see Reinette, River Song) - I expect there'll be a lot more of that.
That's one of the biggest differences between Classic and New Who. Peter Davison (Fifth Doctor) has said that - because at the time he was the youngest actor to play the Doctor - he was instructed not to touch his companions on-screen at all, though he also said that he played the role as if he was in love with Nyssa
As for Tom Baker, watch his episodes with Romana II (Lalla Ward), in particular City of Death; while there's no explicit romance, the chemistry is blazing. Hardly surprising, since the two of them fell in love on-set and married!
Wendy (who, for the record, loved Donna and is very sorry that she's gone)
