what it'd be like if they accidentally married and made a baby that destroyed the universe. Though obviously Adric was their child too.

Hahahahaha!!!!

And the bit I saw of End of Time did convince me at least that the Doctor was madly in love with Donna. - You've not seen all of it? (And which bit? I'm curious...)

It's been stated a lot that there is no canon in DW, so I suppose that makes it easier to 'bend' it!