Personally, I think it COULD work. However, with the writers' track record on writing romance, I'm not so sure. I do agree with the comments posted above about CBS being a conservative network, and some of the fans being conservative. However, I think that could be worked around. Other shows have had gay couples on them and it's been no problem.
My main problem is the writers' track record of botching Canon relationships. It seems that every single canon relationship is dysfunctional in some way, or either born of dysfunction. Catherine's taste in men, the idea of Sara getting with Grissom and her life is magically a-ok all of a sudden, Warrick's marriage to Tina, the fact that Nick only has sexuality when it can advance a storyline, the DannyLindsay debacle, Stella's abominable relationship with Frankie Mala, etc.
I can see them getting Danny and Flack or Nick and Greg together, and then everything getting botched, like they did with Danny and Lindsay.
That became a HUGE trainwreck. I can totally see them doing that with a pair of main characters.
I'd love to see something happen between Danny and Flack, especially because Lord knows that they're so incredibly in love with each other. The way Flack stares at Danny, the way Flack is the only one Danny can trust, etc. I can see it. However, it's the fear of the writers botching it....
That's why, I think they should include some sort of LGBT relationship with a main or recurring character. That's what's irksome about them deleting the Bobby Dawson scene from Grissom v the Volcano... Something nice, just a throwaway remark, but....boom.
I think Adam from NY would be perfect. That little line in "DtRH" where he asked Mac if he wanted a male or a female character was so cool. Says that he's experimented before. It would be nice if there was a little line like in "Oedipus Hex," where he said he'd dated a Suicide Girl before, that he'd dated a guy. That would so be funny.
Of course, there's also the theory that Adam and Sheldon have been going at it in the Supply Closet for two years and no one knows....
Still, I think it's way overdue for there to be something where there's a main LGBT character or they're not a victim.