There has been no indications that the game will move to a sandbox format. The re-work will take events over the first 7 days and make it into 21 days or more. It will fix some of the changes with the models. Nat's Hair, MC dick size, Emiko's model, Ruby's model and I am sure others too. It will change the way some of the events happen too like Rachael's first interaction and many others. So many other changes too like the day tracker so you know what day it is in game and other fun quality of life changes.
Personally I think it is best to take a wait and see approach to be honest. I am looking forward to these changes, but I understand how others might not be interested in them.