Well, I've only seen a smallish fraction of Old Who so I can't completely speak to that. And it's partly the sexual component and partly the emotional one that I just don't think were...in place to have that kind of love before (ignoring the meta textual reason why now it's gone there).
in time (maybe a series or so)
My thinking was more on an in character time, which isn't really the same as how many series it is to the viewer, but I was thinking much longer than that. If we accept that Rose is The One for him, then she's his One in 900 years, I don't see how he could reasonably go there again for quite some character time.
But also on a viewer level, it's going to take me time (and not being written by Moffat) to accept the Doctor falling in love again. That yeah, a season or two at least, but some in character development to make it okay to go there.
no subject
in time (maybe a series or so)
My thinking was more on an in character time, which isn't really the same as how many series it is to the viewer, but I was thinking much longer than that. If we accept that Rose is The One for him, then she's his One in 900 years, I don't see how he could reasonably go there again for quite some character time.
But also on a viewer level, it's going to take me time (and not being written by Moffat) to accept the Doctor falling in love again. That yeah, a season or two at least, but some in character development to make it okay to go there.