I agree Revan should be a man, but for completely different reasons. Why? It's better for the story to pick a gender and stick with it. It worked in KotOR2, but only barely. Personally, I felt the issue was rather strained at times. That's not saying that Obsidian didn't do a good job, it's just that I think it'd be better if they had simply said Revan was a gender and a side. If there is a sequel to KotOR2, conneting that storyline to the two previous games will be even more difficult. By letting the player pick what Revan was now, they are basically painting themselves into a corner because they'll be expected to let the player do it in KotOR3 as well. Not to mention the exile, meaning even more combinations.
Basically, what that means is that it'll require some *very* good writing to untangle, or that Revan/the exile will be mostly ignored. Like Revan was in this game, more or less. The latter will of course leave a lot of questions unanswered, and I wouldn't like that.
So, why a male rather than a female? Well, it doesn't really matter I guess, but I simply thing the Bastilla/Revan relationship is more interesting than a Carth/Revan relationship. If Revan is evil, it's master/apprentice. If good, well, I'll leave that to your imagination. I don't really give a damn about what gender is more suitable for a sith lord, as far as I'm concerned, a woman can be just as strong-willed as a man. A man could possibly have a pure physical advantage, but that's pretty much it.
I haven't decided whether I'd prefer a light or dark Revan yet, but I'm kinda leaning towards light because it's more familiar.
Possible spoiler, read at your own risk if you haven't completed the game at least once: