I am writing this on my phone, so please pardon any typos.
I've just gone to see a piece of music, which I won't mention the name of here. It was an interesting idea and technically competent and well-rehearsed, but it fell a bit flat in performance. The best moment of it was a long pause in the middle. The conductor and performers froze and the audience held its breath, waiting. What would happen next? Was the piece over? Was it still going? I had a composer once tell me that pauses add drama and this was the first time I would agree with that pronouncement.
I had a look at the score afterwards and it had a bar of rest with a fermata over it (that means 'hold this') and a asterisk to a footnote that said to hold it much longer than seemed reasonable or necessary. Interestingly, and i would say not coincidentally, this did seem to be the only thing not precisely notated in the work. Everything else about the sound production had been pre-decided by the composer and the ensemble was carrying out his eaxcting instructions.
This does seem to be the dominant theme of 21st century music composition. Composers seem to want complete control over musical output. Some, like Ferneyhough with his total complexity, approach this at an ironic distance. They intentionally overnotate in a way they know is unplayabe, to produce a specific kind of stress in the performer. But more recently, the trend is to overnotate but remain playable with the sincere intention of getting exact performances every time. Or, at least, to control what elements are exactly repeatable and treat the freer parts as one might treat a random generator or a markov chain in a computer program.
I played very briefly in the Royal Improvising Orchestra in the Hague and I have very positive things to say about that experience and the other members of the group. However, the control thing was still evident and creeping in. They had borrowed from another a group a very large set of hand signs, designed so the conductor could tell the supposedly improvising players what to play. Indeed, with those hand signals in use, it was no longer accurate to say that the players were improvising. Instead, the conductor was and were mechanisms for carrying out his musical will. Fortunately, that was only a small aspect of our performance practice. When we were doing this, we all took turns conducting, so we got a tradeoff and still were improvisers, at least some of the time.
I mentioned above being treated as an aspect of a computer program and, indeed, I think that is the source of the current state of affairs. Many younger composers (I'm including myself in this group, so read "younger" as "under 50") have become reliant on score notation programs and write music without being able to read it very well. With MIDI playback, it is possible to know what notes will sound like together even if you can't read the chord or find the keys on the piano.
The major drawback on relying on MIDI renditions of our pieces is that they sound like MIDI - they are precise, robotic and unchanging. Pieces that are written to sound good for that kind of playback often don't work very well with live ensembles. One solution to this dilemma seems to be to treat ensembles more like MIDI playback engines, rather than adapt our style of writing for real conditions. This is a failure of imagination.
Those who are pushing notation and musical ideas in new directions are not so naive as the above paragraph suggests, but we still have become accustomed to being able to control things very precisely. When I write a musical structure into a program, I know it will be followed exactly. when I want randomness, I have to specify it and parametrise it precisely as well. In the world of computer composition, adding randomness and flexibility is extra work.
For humans, it's the exactness that's extra work and one that has faint rewards for audiences and for performers. It sucks the life out of pieces. It makes performing dull and overly controlled. It is an unconscious adoption of totalitarian work practices, informed and normalised by the methods of working required for human computer interaction. The fact that most professional ensembles barely schedule any rehearsal time does not help with this phenomenon, as they do not tend to spend the time required to successfully interpret a piece, so we seek to spell it out for them exactly.
Composers would do well to step back and imagine liberating their performers, rather than constraining them. We would also do well by learning to read scores. Computers are fine tolls for writing, but could you imagine a playwright using text-to-speech tools in order to create a play? Imagine what that would do to theatre! I think that's happening now to music.
But, as in today's performance, the most magical moments in performance are the ones where performers are empowered. If you don't think you can trust them, then you've picked the wrong performers or written the wrong piece. In the best musical performances, the emotional state of the performer is followed by the emotional state of the audience. Give them something worth following.