And now, my responses.
1. The audience should feel free to applaud between movements.
Maybe. Perhaps after the first movement of a concerto, if there was a cadenza involved. Perhaps after each item in a song cycle or series of dances. It can show that the audience is following and affirms the conductor's interpretation of the overall piece as it progresses through the movements. But I think it would be difficult to derive a new standard here. Applaud only after loud, fast movements? Temper your applause to up to fifty percent of what you would give at the very end? What if people start to applaud just as the conductor preps the downbeat to the final movement? I certainly think there's room for a shift from a universal frown, but where to redraw the line is a challenge.
2. Orchestras should tune backstage.
Should they also refrain from meandering out to the stage fifteen or twenty minutes before curtain and quietly (or maybe not so quietly) playing this or that passage from the evening's program? To me, the entrance of the conductor is what signals the true start of the concert; the tuning does not affect my hearing of the actual pieces of music.
3. We should be able to use mobile phones.
People are doing it anyway. Is an orchestra really going to lose money because a few quick photos, even from the new iPhone 6, or even some 15-second Instagram recordings are circulating on the Internet? I would even say orchestras should create hashtags for each program in their season and ask people to tag their posts from the concert accordingly! Appropriate etiquette must be observed, of course: silent mode, and lowest brightness, so as not to disturb people who, in their own discretion, wish to focus solely on the music and musicians, and react later.
4. Programs should be less predictable.
This idea has merit. While it is true that the repertoire is often the selling point, a well-chosen theme, with the exact pieces announced from the stage, can sell well also. Not to mention headliner soloists! Seriously, does it really matter what Yo-Yo Ma is going to play? Yo-You Ma is going to play!
5. You should be able to take your drinks inside the hall.
I will not embarrass her, but I was once at a concert with a friend and no one prevented her from bringing her slushee into the hall after intermission. There was an audible slurp during a quiet moment of a Dvorak Symphony.
As long as straws are not involved, I have exactly zero problem with folks having their coffee or tea or beer or cocktails in the hall. No aluminum cans, though. Very tacky.
6. The artists should engage with the audience.
Absolutely yes. I would love it if conductors would say a few words about how they arrived at the interpretation they are about to present. Do keep it short, though. And not for every piece on the program. And yes to mingling with concertgoers after the concert. Probably not backstage, where stagehands will be at work and dressing rooms will be train stations, but why not in the main lobby?
7. Orchestras shouldn't play in tail suits.
Here I must hold out as a traditionalist. Uniforms are important. I really have no idea what purpose the tall white hat serves in a kitchen, but it is part of the package.
8. Concerts should be more family-friendly.
Yes and no. I firmly believe that every professional performing arts organization should devote part of its time, energy, and resources to programming suitable for children. But on the other hand, some works of art are hard to understand, and take more attention, patience, and critical thinking. Those works are part of the canon, and just because children are unable to understand them, adults should still be able to engage without the children around.
9. Concert halls should use more cutting-edge technology.
There is merit in this idea. Depending on the configuration of the hall, I have no inherent problem with image magnification (though sometimes seeing the full breadth of the orchestra from the highest balcony, with each bow moving in unison, is very much worth being far away). Downloadable content, yes. Digital acoustic enhancements, sure. As long as it all supports the music, rather than creating something that is more artificial than not.
10. Every program should contain a contemporary piece.
Maybe. As long as the inclusion is for the sake of presenting quality music, not for the sake of presenting a contemporary piece. Present the best music from across the ages, rather than meeting quotas.
What do you think about all those ideas?
Brönnimann himself responded to some of the comments on his original post; his responsive thoughts are worth reading as well.