Four subs? Wow. That's a pretty large space you have as well, and I guess four subs helps fill the room and balance the sound. From what specs I saw, those Seatons don't go that deep in bass despite their size (50Hz for the Seaton C12).
With more pieces comes more complexity, so downsizing can help simplify things. Given the theater you have now, I would say it's an awesome experience to watch/listen. The room itself looks inviting. But once you're in the new space, you can have something that will be just as satisfying which fits the new space.
Would downsizing mean getting rid of equipment only, or replacing something with something else more efficient space- or performance-wise?
VPI, Grado, SME, Pioneer Elite, Magnum Dynalab, Day-Sequerra, Oppo, DVDO, McIntosh, Telefunken Black Diamond, Mirage, Kimber, Transparent, MIT, Pangea, Shunyata, PS Audio, Furman, Sanus