I think it's funny that her thread wasn't very active either, like idk, no one really mentioned romancing her that much w a m!inquisitor until the news of her being a lesbian dropped.
Well, I can speak only for me. I'm reading this topic for a long time, but as english isn't my primary language, I do not take part on the speculation. Then news spread and now I'm here, for the moment. Now we know almost all we can know about her before the release...
The irony was funny though, all the "DA2 bi romances were awful & unrealistic, we need set orientations" then when a pretty female party member is gay its "i wanted to romance with my male character, how dare BW take away my choice by making her gay, she should be straight or bi" 
I'm not against gay companions. And not against bi, but for ME, and i'm talking only about ME, Anders felt unnatural (but that's not the thread here and I can respect whatever you think about it). I'm just a bit disappointed because it's the second game we can play as elf and again we can't have a straight elven relationship when we play with a male elf (female elf Warden had Zevran and maybe the Inquisitor have Solas). I really like the elves from Thedas and I'm totally supporting them, so I would like to have this kind of relationship sometime. Maybe on the next Dragon Age, who knows...
That being said, I still think Sera is the most cool companion until now and I will keep my plan to take her and Cassandra with me most of the time.