Besides. NPCs in DA games have never been player sexual, as far as I am aware, so Bioware never really got into *that* part of the discussion. Arguing "well this character have these particular preferences" is much easier than saying "oh, sure our NPCs are player sexual. Why we have no sex scenes with the dwarves? ... We're afraid associating dwarves with children for nudity scenes" as the latter can be really tricky when it comes to the little people community and today's representation ideals in general. :|
EDIT: Besides... Is it not in the Faerûn universe that female dwarves have beard? *thinking* It comes from somewhere and although I do hate it with a passion I do not remember where the trend came from.. . _ .
DA2 companions were playersexual and in that game you still couldn't romance Varric. But yeah with DAI they went all in with the "this character has particular gender- and race-preferences", which helps them to sidestep any potential problem elements. Though 3 consecutive games where there's no dwarven npc with a romance scene is clearly a intentional decision on Bioware's part...
I think it just really comes down to the models. If the models look like children, that's problematic. If the models look like small adults (dwarf-, human-, or other-like), then that's fine honestly. Short does not necessarily mean child.
I think it's a Tolkien thing that female dwarves have beards...?