I rather think, with a second look, that your present arrangement is the best. I would work the present living room with the brick area as the HT and leave the sliding doors and traffic to the dining room. But, man, is that table to scale with the room? I would recommend something round, with a couple of sections you can add with a crowd.
If your rear surround speakers have to go above windows, use wall brackets and fire them downward. The side surrounds might go on solid walls either side of the couch.