I've been thinking about the race-gating a little bit, and have at least a partial theory. Could the race-gating be related to adding on the additional playable races? Beyond the obvious in that now there are more races, of course.
Before the other races were added, you only had to deal with a human Player Character, and could, thus, build a specific story around one.
So, let's take Solas. If Solas were an LI and his story written before the additional races were added, maybe part of his romance takes place in the Fade, or a lot of his romance dialogue has to do with taking the Player into the Fade, or teaching them how to use the Fade. Then you add in Dwarven Player characters. Dwarves don't dream, and unless our glowy hand suddenly makes dwarves capable of it, that means that there is no way the already-written romance plot can work with a dwarf. Thus, story-related race-gating.
I'm trying to think of other examples, but I can't. Perhaps Vivienne talks a lot about how dating an elf or qunari would be political suicide. Do you think that this could have something to do with it?