i too hope they implement this
1. to be accessible even without controller (i.e. swipe up/down could be used) and
2. to be accessible in the void as well, so that every person can choose for himself how big he wants the screen to be. i do like the void, but it kind of bothers me that the screen is smaller than in the main cinema. sure it makes sense to not have the picture "attack" you too much, but on the other hand, theres movies that attempt to do just that, i.e. gravity.
so, this should be an easily accessible user setting in all theatres including the void, IMO. for some movies, id like to sit in the back of a cinema with some distance, i.e. TV series that generally tend to do more closeup than movies do. for others, i might want to watch them silly close in the void so that they almost fill up the entire FOV, maybe even a bit more than the cinema default does (that would be gravity

)