But Bioware never said anything about being fair towards player races
True but what are the reasons behind race gating that we know? Story reasons and animation, IB was going to be race gated cause it was going to be to hard to animate him with all the different races but that has been fixed so now we can only figure that the 2 race gated LI's are for story purposes. Sera is an elf she along with humans would be the easiest to animate in love scenes and the like. We don't know Sera's take on humans, but from what has been said about her she isn't a serious individual unless she needs to be or that's what I have gotten from her so I really don't see her being the typical elf and having a dislike for humans so that is why I see her being available to every race or at the least humans and elves.
Only race gating I could see make sense
Cassandra- she may just be into human men, she actually comes across that way to me at least.
Vivienne- I could see her being human only, seems to fit with her character and stance.
Varric- If he is a love interest I only see him being interested in female dwarfs.