The chunky walls on the left and right sides of the dining area would make the perfect place to hide stacking cavity sliding doors. These doors could be used to close the kitchen and sitting rooms off from the dining room. This could be especially good in winter if you incorporate a fire place in the theatre/sitting room and want to keep the heat in.
There is one major flaw in this design. Unless you use a flat roof, you will see the roof line through the left and right upper windows :/
|View of the kitchen, dining and theatre/sitting room|
|View of the dining room into the theatre/sitting room|