Kitten probably, because it feels more fitting to Ashe's character, and also specially since Natasha is unlikely to be in this update. Ironic that I like the Kitten route best when Natasha is not around considering that she is the one that gives Ashe that nickname.
Siren does the content with Evelyn better imo and of course we all want Ashe to start growing past her insecurities, and CQ do be wilding as a route.
But more than anything else I'm curious if the game is structured any different, if I feel like it is still doable, I will be updating my
route-split remover mod so that you can get scenes from different routes in the same playthrough.
NOTE: I will need to update the mod for it to work with the new update, keep your vanilla game save files separate from your modded save files. Loading a vanilla save of the new patch on the modded game will not work correctly, same for loading modded saves in the vanilla game.