Where is the Magic in our minds? The words bored, tired, disappointed as mentioned in your research coming from judges, competitors and audience may tell
In dancing judges have the final word and the main focus lies on the comparison of assessment and application of skills of the competitors on the day. Declaring the winner by use of the skating system (in principle a majority decision). The judges will place the dancers in order of merit, not assess the individual quality, but the order. What better way to do this than by seeing all these couples at the same time, under the same conditions?