Difference between today and yesterday.

I believe musicians might disagree on an orchestral recording, but a direct recording of a flute at a microphone is going to have all its components intact, barring a bad recording. Also, a "good" recording of the human voice is also going to have all its components intact.
And, assuming that someone knows what they sound like when recorded, it is unlikely -- although we must allow for hearing differences -- that someone will not be able to discern which speaker sounds more "true to life."
The nice thing about clasical (and opera) musicians (some) is that they are not distracted by the razzle-dazzle of many audiophiles, plus they have one very important benefit: they hear music LIVE constantly. They need not be concerned about "more bass" or "better soundstage" or other things that audiophiles (myself included) place so much emphasis on, while ignoring that a voice unquestionably moves towards you through space. I have never heard a voice that does not project in music, since projection is de riguer in opera, all the while maintaining the line and the volume.
It's unlikely that a classical singer/musician would not recognize the musical capabilities of one speaker as superior to another, although things like tone and timbre can be a matter of personal taste in reproduced music.

Gbmcleod,
I agree with what you said and would like to add something.
My all time favorite listening experience was with the mbl's. Before I get darts thrown at me let me just say that whatever was playing I got into it. I found myself enjoying rap and hip hop, music that I never liked, but the mbl's presented it in such a way that made me enjoy it. That was the case for all the music played. So when Gbmcleod mentioned musicians don't look for "more bass or better soundstage", neither did I when listening to the mbl's, probably because my ears didn't have to fill in the voids or missing nuances or details whatever cues we hear when listening to the real thing. Therefore that is the holy grail for me, thankfully I have it now so I don't need the mbl's , but I do need a larger room, life isn't perfect.

I think speakers that are older were built better.Case in point,my old Polk Audio SDA1 monitors are built better than any new Polks.(wood finish instead of simulated wood plastic wrap crap,metal backing plates for SL1000 tweeters instead of the cheap plastic mounting plates of the newer models)Just try to pick one up and you will also see what I mean,these speakers weigh close to 90lbs. apiece.I doubt to many polk speakers today weigh that much.I guess I am saying is they do not build them like they used to.