elf(especially dalish) romancing humans? hell no
dwarf(especially who was not raised as castless and whole life live in Orzammar or Sharok as some noble) romancing qunari? hell no..and there is no common and rare for them to romance humans...some as we know from DAO was romance with elfs but even this is not far from rare as with humans
mage romancing templar/seeker(anti-mage person like fenris and those who have all reason to not romance mages or for mages to not romance with those who kill them and serve in order what inprison and kill them)? hell no, this is sick
i would not even talk about everyone is bisexual or gays when it not make much sence if we would talk about realism
gating is make sense and even if i would not mind and want all have anyone so noone would have problems i understand that we must stop fenris and anders, merril situations when romance with them not make sense at all...give presents not change who you are and what you do and Li must stay for what they are fight and belief...Vellanna as Merril would never romance humans, Anders with Morrigan would never romance templar zealot and Fenris as Cullen would never romance apostage or blood mage exept you mind controll him..even be friend with them would be merely posible
But if we would make gating system for the realism we would need more LI option(companions them would be or not) for the more realism because srly when we have a choice to be one of the 4 races(8 heroes 4 males and 4 females), have 2 damn kingdom and many factions to side with,...this is not Hawke in 1 Kirkwall anymore who have the whole options of Li for any taste of races and mages/nonmages exept dwarves and Qunari
you cant give players to romance 2 female andrastian human non-mages...females have male elf, male Qunari and 2 really different humans males and not have only dwarf male, but males nonhumans and mage have nothing exept 2 andrastian human non-mages who is not so really different by their nature and beliefs and created mostly for human and non-mage inquisitor