Too many speakers for home theater?

I just moved 1500 miles east into a new house that allows me to have a dedicated home theater room. My previous home theater was a 17'x12' multi-purpose family room with multiple doors, hallways, etc. My new room is 15' wide x 22-1/2' long with 8' ceilings and a single entry door. Currently it is a 7.1 system with Tannoy MX4s in front, MX1s on the surrounds and MX2s on the rear surround. There is an Art of Sound subwoofer and an MXC center channel. The seating area is 12' from the front wall and 9-1/2' from the Sony Wega 36" TV. The side surrounds are just over 16' from the front wall facing into the room and the rear surrounds are in the corners and angled toward the seating area. The side surrounds are on speaker stands 30" off the ground and the rear surrounds are on shelves 53" off the ground.
Now my question... At times it seems that the surround information is somewhat localized and congested - would I be better off foregoing the side surrounds and using a 5.1 system? The rest of the system is B&K 317 and Arcam DV89. Overall from the seating position the frequencies with my Radio Shack SPL meter are reasonably flat down to about 20 Hz with a slight suck out at about 56-60 Hz. Other than carpeting, furniture, bookshelves, pictures and wall hangings I don't have any official room treatments. Your thoughts? Too many speakers? Any ideas? Thanks guys!