Im sticking with Cassandra and Cullen as being race gated as their are more than enough humans to romance within this group.To those who claim we know Cassandra's character, we know nothing about what she finds attractive or not, most are just speculating because of what they want to do, but it's not about what we want, it's about how the writers envision these characters, what stories this characters hold to, this is what makes them (all companions) dynamic, if you want romances that just go whatever way you want look to skyrim.. Where any race combination or sex can marry any pre-determined marriage available npc.. yes, despite actual known racism, and political/cultural taboos being present in the game. Don't you guys want these characters to be more than yes and no pillow warmers? A Heterosexual race gated LI is not a deal breaker to me, i think most people are more into the legacy character idea and want it to fit the most bizarre combinations they can dream up.. truthfully, i think BioWare should have went the extra mile and made inter-companion romances, ie companions that romance other companions based on their own interest, assuming you don't fit what they are looking for by the time they find someone else more suitable. !.) It' would reveal what that person is into for future playthroughs, 2.) it's more realistic, that other people would be hooking up to.
Also why is a heterosexual race gated option so strange or unbelievable to people? Truth be told that is very much how i would imagine most of thedas to be, if at all it mimics the real world. You can't honestly believe that every game, the PC just happens to have the largest selection of its LI's be bisexual, or whatever term describes someone who is completely open minded to interracial relationships. If that were the case I would think that there would be no problems between races in thedas at all, but thats obviously not the case, and while im not promoting that companions have some kind of inability to work with other companions, they doesn't mean they should ignore such things when it comes to whom they find attractive. Notice i said find attractive and not love, as to me the later is more of a familiarity with a person you have come to accept or understand.
Also with 4 potential races to play it's not like if one of both Cullen and Cassandra both played the Hetero-Race Gated card, that it would be the same exact combination. Cullen likes Elves and Humans, so lets pretend he excludes Qunari and Dwarves (When did he ever say he didn't like Dwarven Women?) Cassandra might be into Humans and Dwarves. (That really only leaves out Qunari for the both of them and thats hardly a huge slice of the potential inquisitor race/gender combination)