A very interesting article. I wonder if the effect of using staked line-arrays in such rooms could enhance the sound, as it would radiate in a similar way as an unamplified source would.
Line arrays are used quite regularly in halls designed (at least in part) for unamplified performances as they are very rider friendly and we can gain the benefits of an array. They can be a bit of a mixed blessing. The difficulty has been the extremely wide horizontal which up until recently was almost all line arrays. Too much sound was sprayed onto the side walls with a wide horizonal line array creating unwanted reflections and energy build up. In addition, the rear wall of the audience chamber and any large balcony faces create harsh reflections that are unwanted and send energy directly back to the stage (but late in time). With newer DSP software that allows for avoidance zones in coverage and tighter horizontal pattern control, the sound can be tailored well. Some halls still benefit from point source coverage, it depends on the shape of the audience chamber, depth, materials, etc.