What I am looking forward to is Ashe's persona growth. The different personality that start to emerge slowly. Some tipping point where I can tell: Ha! there is the choice of going where she wants to be. Beyond the simple difference in text I want to see that difference come to take shape and form. That will require me to go through paths I am less keen on, but in the long run I have a feeling it will heighten my enjoyment of the game over all. But I will do my prefferd path first anyway to get the surprises of the update while planning to enjoy it rather than be supper analytical.
If I go by content, Lexi is among the ones I am most looking forward to, but so is Vanessa. Natasha is an interesting one. While what is planned on the sub and cuck path is already advertised, I am looking forward to know how she will react on the Siren path. (I don't remember the in game names of the two other path from the top of my head sorry.) I wonder if there will be some interaction with her in a sexual context on that path. I guess not soon for that though and it might not be outright fucking either.
While I do have favorites, I am looking forward to pretty much every characters but it might not necessarily be for sexual reasons.