Would a musician be better qualified

[jochanaan]

...I'm not aware of many indicators for expression...

You obviously haven't looked at a Tchaikovsky or Mahler score! Pyotr Ilich's dynamic (loud and soft) markings range from ffff (used frequently in the Manfred Symphony) to pppppp (in the Pathetique Symphony's first movement).  And Mahler could write ff and pp for different instruments at the same time!

[Ten thumbs]

You obviously haven't looked at a Tchaikovsky or Mahler score! Pyotr Ilich's dynamic (loud and soft) markings range from ffff (used frequently in the Manfred Symphony) to pppppp (in the Pathetique Symphony's first movement).  And Mahler could write ff and pp for different instruments at the same time!

Volume is not specific to expression. It is quite possible to play a full range from as many fs to as many ps as you like without any expression whatsoever. The best I've seen is specific instructions such as 'espressivo' but these leave the manner of it to the performer.

[jochanaan]

Volume is not specific to expression. It is quite possible to play a full range from as many fs to as many ps as you like without any expression whatsoever.

I suppose it is--but I've never been able to.  To play music "without expression" requires a major effort--and even that can be very expressive, as in Neptune from Holst's The Planets.

The best I've seen is specific instructions such as 'espressivo' but these leave the manner of it to the performer.

Every good performer develops his own stylistic methods of providing expression; the better the player, generally the more individual his/her expressiveness.

[Ten thumbs]

Every good performer develops his own stylistic methods of providing expression; the better the player, generally the more individual his/her expressiveness.

Exactly so. This, as I was saying, is the one area where the performer can do his/her own thing without treading on the composer's toes.

[jochanaan]

Exactly so. This, as I was saying, is the one area where the performer can do his/her own thing without treading on the composer's toes.

Actually, in almost every aspect of music except the actual written notes, there is room for individual variations and flexibility without any disrespect to what the composer wrote.  For example, the famous first movement of Mozart's Symphony #40 is often played at about 100 beats per minute to the half note, more or less (I'm guessing based on my memory of recordings I've heard and my sense of pace and timing), a legitimate choice; but I can imagine a performance at 120 or even 132 bpm that would still follow Mozart's written indication of molto allegro.  Yet if a group plays that movement much slower than 100 bpm, it's arguable that they're not really following Mozart's written tempo indication; and much over 132 bpm would be more presto than molto allegro.