So many people seem to miss the subtle flavors of the Siren path. Do I prefer Kitten and believe it to be more than likely the "canonical" route? Absolutely. Does that in any way shape or form detract from the Siren route? Absolutely not. The key, however, lies in the subtle distinctions. Such as in the scene with Lexi on the beach, Ashe mentions how Lexi's responses begin to stir something inside her. It's a slow, gradual build. For me, in the current state of the game, the masterstroke was in Fiona's scene with Ashe before the party. Why? Because depending on your choices on the Kitten route, Fiona offers to get Ashe a towel (If you let her cover you again). However, on the Siren route, it's Ashe who offers to get one for Fiona.
Now, why is that? Well in order to answer that you have to answer one question, but you have to answer it from the view of the BDSM community... Who provides aftercare? It is NEVER the sub who provides it. It is always the dom/me. However, in this instant is a hint that the dynamic between her and Fiona is starting to shift.
I still remember several months ago someone whining because Siren Ashe didn't top Fiona, and they think she should have. I mean, that on it's face is completely ridiculous, because all the way back in Chapter 1 or 2 Ashe muses to herself how Fiona has never been interested in futas, and is probably definitely not interested in her, then wonders is she would be if she told her about her pussy. So, THAT would be another route that changed a character's core design, all in favor of trying to satisfy certain people's personal preferences.
That's just my two cents though.