I've always maintained that Tav should have some unique experience of the main plot and story that no other origin gets. After all, every origin has unique tags. It just so happens that being Tav let's us choose any combination of them.
This is it exactly! This is what I'm trying to say as well. Interractions based on Tav's race/class tags are not meaningful, because those are generic to ANY character that has those tags, including the origins and any mercenary character we may create and include in our party. There ought to be things in the game, meaningful and important things that are central to the game, that are unique to Tav, things that no other character gets (be they origins or Durge or a mecenary or an NPC).
