I'd personally have preferred a two part main story update right away, mainly because I think that the ending of the main story and the prom should be done towards the very end of the game and not "now" somewhere in the middle. It would have been fine to advance the main story, set everything up and create a nice cliffhanger for a future update.
I've still got a small hope that 0.20.0 will take longer than they anticipate and that they may drop 0.20.5 to some later upate, but that's probably only me wishing things.
While Diane's story did feel a little incomplete (mainly because she still lives on her sofa...), I personally liked Jenny's update because it finally cleared up the mess her "story" was before and made it a lot more conclusive. It just didn't feel new because most changes were rather small. Eve on the other hand was really nice to play and I'd even perfer her story to Roxxy's.