As you wrote, "These shortcomings were outside the purview of the performers, as the sound was not under their immediate control in the concert." You are totally uninformed!
If you had done your research you would be aware the only items onstage being played live consisted of the grand piano and Mr. Pickard's vocal mic. (AKA lip-synching the backup).
The drummer and synth player were playing along to prerecorded backup tracks provided by a mini-disc player on stage! The vocals, the microphones under the piano that were under Mr. Pickard's complete control from the stage at all times and output of the mini-disc tracks were actually being sent to a 16-channel mixer on stage operated by the synth player just behind the grand piano.
The piano, mini-disc, synth, drums, vocals were combined on stage, the balance set and the finished mix sent directly to the house P.A. with specific instruction not to vary the volume. The house P.A. operator had no control over what the performers wanted the audience to hear except for minor changes in volume. In many ways this makes for a much richer sound and is more reliable than trying to play everything live.
In rehearsal Wayland Pickard apparently spent a considerable amount of time working on his piano microphones and was responsible for the tone, balance and clarity of the piano sound. What we the audience heard was exactly what he wanted, tonal quality and all! If you want to poke at someone about the, "overmicing of the piano," "hisses and hums" or any of the other technical problems … go to the source, the artist.
I, like the majority of those in attendance, was fooled by the magic of the recording studio and never knew how technical the performance really was.
I, with other Valley musicians, have played several times for functions in that ballroom and Barbara Worth is a beautiful facility but acoustically, Carnegie Hall it's not. An unamplified piano in front of 300 people won't carry 25 feet! I was impressed on just how clear the P.A. company had the sound in what to local musicians is a very tough room. I do agree there was several times it got very loud, but who was doing the mix! The artist onstage.
According to the local guys running the P.A. and contrary to the "Tower of Power rock concert" mindset, the P.A. used that night — and I guess this holds true to other events around the Valley they do — was sized to the written requirements of the artist and of the area to be covered. … Sounds like you need to go see a real rock concert?
Like I said, we enjoyed your review but let's leave the technical stuff and "possible groaning problem" to the professionals who do this stuff day in, day out, who are paid to know what size system works at Barbara Worth or any other venue and are still willing to take the heat in the reviews for what the artist does.