Does Will have a penis, or is it smooth down there? That's how he is portrayed - a pathetic excuse for a gay men, utterly dependant on a heterosexual woman. That's right kids, you can't survive without a woman to steer you through life. And God forbid that Will ever be seen to do more than (very occasionally) kiss another man.
As for his relationship with the Taye Diggs character - by this point, I'd long since lost any interest in the show. In their portrayal of an interracial relationship, Will & Grace failed miserably. Will is precisely the sort of gay man I find abhorrent: as far as I can see, all his friends are, and always have been, caucasian. But suddenly he's hooking up with a black guy. Is it a lil something to giggle about with his fag hag Grace, perhaps? Here is what's wrong with many interracial relationships: unless your normal social group is racially mixed, you have no business jumping in the sack with someone of another race, because it then becomes objectification. It isn't about the person, it's about the flavour. In other words, if all your friends are caucasian, and you start a relationship with someone who is black, then that relationship is built on a lie.
I haven't seen the Taye Diggs episodes, but I can't imagine that his own group of friends - even if they were depicted - were shown to be a healthy mix of colours. In fact, I'd bet my collection of CocoDorm and Bel Ami DVDs on them being a bunch of middle class white fags.
The character of Will is an abomination, representing much of what I hate about gay men - self-absorption, neediness, weakness, self-loathing.
Thank goodness he's gone...