On the first point, Robert E Greene said this in TAS in his review of the Janszen zA2.1: "One of the mechanisms by which music gives the impression of getting louder is that the distortion produced by instruments themselves increases as they are played louder. An unthinking listener can confuse messenger and message and can start to believe that components with distortion that remains low as levels rise are “undynamic.” I am not making this up. A well-known reviewer claimed for example that the Sunfire Signature (which could put out 2500 watt pulses) was undynamic compared to tube amplifiers. You can form your own impression of what was going on there."
If you don't know Greene, he is a professional mathematician and semiprofessional violinist. He knows sound, he knows theory, and he actually measures the gear he reviews -- though TAS doesn't print measurements.
Typically, panel speakers don’t have as wide a sweet spot as cone speakers. That’s one big reason they are not as popular: they are more suited to serious listening than providing music for a party.