The only reason I'm doing that is because the way the room is pre wired. all the ports arr coming out of the ceiling, not allowing me to have any floor/tower/bookshelf speakers. Will this negatively affect the sound that much? The only speaker not on the ceiling would be the center channel, right above the tv.
If you are going to have a center channel, then compromise and close
the front left/right channel ports - it is worth it, if you can work it out.
Front speakers up high would be annoying and distract me, as the front
dimensional stage will be un-even and distracting. There will not be an
even sound-plane from left to right, or right to left > the action scenes,
sport events and concert shows, can be weird sounding.
If you are really going to do this, then forget the center channel and go
phantom center, it may be less distracting this way.