If you look at the map I created, you can easily add an additional 2-3 more with enough queue space left. It was very strategic of them to put those newer tents back there. You also have an area behind Trollercoaster that can fit another tent. This year's HHN also utilized all but one soundstage for the event... so once FF coaster opens and they get some queue space back, they can potentially add another house back there.