Honestly, I just don't know enough about the characters to really judge this kind of thing properly, but there are two things at first glance I would like to change but again might not once I know the characters better.
1) I know you said to not change sexuality, but Serah is the cutest female character in the game so far, out of the companions/advisors at least, and I prefer playing as male characters usually so having her as an option would have been nice.
Ofc maybe that just fits her personality or something, I don't know enough about her, and like I did in DA:2 I might just play through again as a female and like her better then my male, so we'll see (ofc though the male Qunari look badass as heck, so doubt I'll switch anytime soon lol)
2) Having the Iron Bull romancable by literally anyone seems like utter and pure fan service to me. Some big brutish and comical Qunari warrior can be romanced by any race of any sex? Seems like an incredible reach lore wise to me, but ONCE AGAIN maybe that's just his character and it might fit him well as it did Zevran in DA:O, I simply do not know enough about him to say for sure.
Other then that I have no issues at all with the romancable characters. Originally I was surprised Varric wasn't a romance option just cause of how popular he is, but no one can beat Bianca in Varric's eyes, so it makes sense to me lol