Sometimes when romance becomes explicit on screen it becomes also unfortunately cringe-worthy, and I definitely see the appeal of the pairing options remaining open. Though in general I'm not much of an unconventional pairing shipper. I mean, my favorite het pairing is Farscape's John/Aeryn and I didn't mind at all that they got together on the show. OTOH I would have been much happier if the X-Files had stuck with UST between Mulder and Scully, and not because I liked some other pairing in particular. I guess for me it depends a lot on how the romance is realized and whether what I like about their characters and dynamic gets twisted and diminished by the romance.