While I agree that gradually they became closer friends since about S5, and I liked the concept in 'parallels', a relation between them in prime-universe just felt contrived to me -- kind of a 'let's pair up cast X and Y for fun and see what happens!'-feeling to it, rather than being a genuine relationship.
I guess I would 've been only marginally more surprised had Worf ended up with Riker, asking Troi permission for that.