First off, I am a pessimist. So I'll put the obligatory "This will end well" in here and be done with it.
Then, I have always been on the side that argues that there is only bad blood in turning characters gay, or replacing them with a minority, if you will. The fans who have liked the old (presentation) of the character feel like they're being told they should be ashamed and that they're close-minded by being bothered by the change. And the supposedly new fans this should draw in would more often than not feel like this is a cheap hook for them to attach to.
I find that both Batwoman and Bunker, introduced as homosexual from the start, worked out very well. It can work out fine, you just have to give the character some care.
That said, I gather that there seemingly is a number of characters that have heavily homosexual undertones that I am ignorant about (the characters and the undertones). Chief amongst which I'm hearing of Tim Drake. I honestly said doubt that he is going to be the one, mind you. Anybody else? I mean, we know it is a reboot, but I doubt that would come totally out of the left field.