I think it's worth recognizing that in terms of something like this, a bisexual may not have the same feeling of void a homosexual does because we can, in some ways, still identify with the heterosexual models we see in at least some of our relationships.
I think too, what a given person wants or needs in terms of the cultural iconography they see is going to vary an awful lot, and we can't make very accurate generalizations based on what those of us who are gay, lesbian, bisexual or transgendered need, because we are a HUGELY diverse group.
But talking about things like staff in support groups, really, is is often going to make a difference. A heterosexual person is not going to have had direct experience navigating a lesbian relationship, nor directly and personally understanding all of the aspects a lesbian is going to be juggling in such. They can be empathetic and supporitve, sure, but the advice they may give based on their heterosexual relationships can often be of limited help.
Do I, personnally, need to know that an aspect of who I am is being more accepted in our culture? Well, it's sure nice, especially when if I have a same-sex partner I have to deal with an awful lot of serious negatives. Having some positives, and seeing some light at the end of the tunnel is somewhat comforting. Yes, some of it might be tokenism for the time being, but it's a foot in the door.
And while I'm not a TV-hound myself, one of the bonuses of GLBT performers or characters existing in such is that they get visibility and thus have a little more power in some respects than some of the rest of us do to get more positive messages out there.
Editor and Founder, Scarleteen
My epitaph should read: "She worked herself into this ground."
-- Kay Bailey Hutchinson