I do like the idea of judges on the field, as long as they are only judging technique, not the actual marching itself. I believe that element should be left for the judges in the stands, because a major part of marching band is the point of view. Imagine if you had to watch a bands performance from the side, it would look terrible unless they were in horizontal lines the entire time, which can be fairly boring (I LOVE diagonals) especially from that stands.
I also enjoy the ring of Domes, I love listening to the bands in the Alamo Dome because it sounds so great, especially when Marcus has their playing feature in the first minute of their show. As from a playing stand point, it is kind of weird because the echo can easily screw up people who listen to the music for cues instead of watching their drum major. I thought it was a little difficult but it just adds to the fun of the performance.