Speaking as someone who falls into the definition of "LGBT" ... no, it's really not needed.
Warcraft keeps most of this stuff in the background anyway, even heterosexual stuff is largely skirted around.
There are a few subtle nods already in the game to "LGBT" characters and I think that's fine. There's no need to force equality or anything. If it fits a character's story sometime in the future, then great! But don't force it or rub it in anyone's face. It's not that kind of game.