Errgghhh... ... ...that's what I'm hesitant about, the 'defrosting the ice queen' trope, and that every new companion/advisor female is available. I really want her to stick by her guns too, have her be too busy for love or think herself above it as Fialka said, but that's my personal wish. I could see the last two be males IF two of the male LI's are race gated and all the female LI's are not. But still... hm... not sure what I really think about this...
That was my first thought, too. I mean, what was the wording? Some of them "don't have time for your business"? That definitely sounds like it'd fit Vivienne to me. I think that theory could be possible, though. Since we got that quote from Gaider on the subject of the race gated LIs, his wording has led me to assume that one is confirmed and one is unknown. I could be wrong of course, but... Out of the LIs we know I would honestly be surprised if Cullen wasn't. I mean, he's had openly hostile feelings towards qunari in the past, and his thoughts on dwarves haven't been very kind either. Of course, if he's breaking away from the Chantry's brainwashing then he could be more open-minded towards them now... But still. I'm going to expect the guy we've heard say nasty things about certain races in the past to be gated against them before somebody who hasn't.
Also, if Vivi isn't an LI, then I'd definitely expect Varric. And imagining him to be race gated doesn't require any stretch of the imagination, since he's all but labeled himself as such in DA2. It's all speculation, of course, but it's an interesting line of thought since they won't tell us anything. 
You know, I've been thinking and have come to the conclusion that I have no problem with all the females either being a romance option or having been one in the past. What I would object to is how that plays out. If Vivienne is a romance interest and falls into being the stereotypical ice queen that is softened and melted by her "true love" I'll be gnawing on my desk in frustration. But, if she continues on more or less as before, being a strong and ambitious woman who just happens to have a pet name for and a few scenes with the PC and remains true to who she really is, I would be thrilled. She remains her own person, enjoys a romantic interlude, but doesn't somehow give up all personal desires for the mighty wang (and/or boobies?) and a house full of babies. Why should she have to change, soften, or find some inner girly nature that her "beloved" alone could tease from her?
Not to be confused with the character growing and changing because that's what she would do anyway. Just hard to imagine Vivienne getting all starry-eyed; in fact, from the little we know I half expect she'd ask if you'd want a sandwich afterwards.
I agree with that assessment! Like I said, it's a concept I'm hostile towards at first (because I resent the notion that every woman is "looking for love," to steal Fialka's very appropriate wording) but may or may not ease up on depending on how it plays out. There's many different types of love and affection, after all. That all-encompassing, starry eyed "true love" might be appropriate for some characters, but I'd certainty not think Vivienne to be one of them. But if she was an LI and her arc went down as you described, then that would work fine for me and I'd have no problems! I'm just wary of the potentially gross outcome because... it's so gross. And so frequent. And I'd be a big fat lair if I tried to pretend that I wasn't still pissed off about the whole harem situation that John had going on in Mass Effect. 
For those of you wanting to see the Gamescom demo without commentary.
-le snip-
Yay! It's too bad that there's not that much dialogue, but it's still great to hear without risking bleeding from the ears!
Solas continues to sound wonderful and look fantastic. And COLE. HE SOUNDS SO PRECIOUS AND CUTE OH. I want to hug him. I am determined to hug him. Especially when he sounded hurt. WHAT ARE YOU DOING, MAN? PROTECT THE CUTIE. 
Also my love for Blackwall continues to grow. We still know next to nothing about him but... GRAY WARDEN. I never lost my mama instincts after raising my little baby birds in Awakening, hah. I SHALL CALL HIM WALLIE AND HE SHALL BE MINE.
In all seriousness, though, I love how reactionary their voices are! It's really great; it makes the world seem that much more alive. 