IDK, plenty of people go to S&S and just hang out, eat and drink before the houses open and do not queue up. I've also had no issue leaving the pen area to grab food and drink and return, and SanFran was especially chill. If you are actually in the house queue instead of a pen it will make it harder to go get a drink while you are waiting. I'm not overly optimistic they can make this work well, especially right out of the gate.
I also think eliminating Express from multi night tickets make S&S worse, as you are more likely to go to S&S instead of strolling into the event a little later and just using your Express.