Siansonea II wrote...
the asari are clearly not a textbook example of the "Orion Slave Girl" trope, and there's a tremendous amount of variety among individual asari in the games.
Yeah, on the contrary I'd argue that almost every asari we've seen subverts the trope.
We've seen asari in positions of power and influence that go far beyond "pandering to young heterosexual males"; even if this was the initial intention (or one of the intentions), many of the Bioware writers (especially Patrick Weekes) have made clear that they try to write strong female characters wherever possible.
I also remember reading around the time of Mass Effect's release that Bioware deliberately wanted to subvert and undermine the "blue space lesbians" trope that had become so infamous in Star Trek and other 20th-century scifi, by creating an all-female species that was the most economically and politically powerful in the galaxy wihile also being attractive. So we have some asari that use sex appeal, but just as many who are badass mercenaries, effective diplomats, brilliant scientists, Spectres, mothers, daughters and lovers.
Even if they were made for teenage-boy sex appeal - and I don't accept that they were, without researching it a bit more - the writers have shown that they can move way beyond it, and the asari characters we see now are probably the most nuaned and deep of all the alien species.
We haven't seen many turians who aren't militaristic, nor salarians who aren't janitors or scientists. Asari might be the most diversely represented alien species in the game.