Yeah, that is a pretty big room, and the 5T is a pretty small speaker for a room that size. Also, I'm not sure how far from the speakers you sit, but with only an 8 foot ceiling, there is ample opportunity for a lot of reflections from the ceiling as well as the floor, so it may be that congestion or the sound could be mitigated with speakers with a more narrow vertical dispersion. I'm certainly no expert, but just a thought. The Monitor GX series does employ a ribbon tweeter, which I believe may have the more limited vertical dispersion. Perhaps something like this:
http://www.monitoraudiousa.com/products/gold-gx/gx200/#/overview
http://www.monitoraudiousa.com/products/gold-gx/gx200/#/overview