Your mention of the flute reminds me of the question of dynamic range, which is one of the most significant factors in making a sample performance sound natural. In fact, dynamics either horizontally with expression, or vertically with dynamic range, probably do more than anything else to make samples sound good or bad. You can take great sample recordings and make them sound absolutely miserable by ignoring what happens in the orchestra. For example, the way woodwinds simply disappear in a Bruckner symphony during the massive fortissimo climaxes. A sample user might think "I've got to allow them to still be heard at least a little" but actually, the oboes, flutes, clarinets, bassoons - they are simply gone in many of these situations because they physically cannot exist next to the combined brass fortissimo. They might have well have exited the stage (though it would be a bit distracting to the audience). And this same "drawback" of actually losing sounds happens all the time in other pieces to a less extreme degree. I think that when one is doing a sample performance, one never wants to lose any of the precious notes one played into the computer, tweaked lovingly, etc., etc. And so there is an extreme unnaturalness that comes with totally distorting the dynamic range.
Another aspect of this is in timbral variation of dynamics - in a live orchestra, even if there is a general mf, a soloistic line in the flute might be played at a near-forte, rather than a p as marked in the score, simply IN ORDER TO BE HEARD. And yet it is played delicately, to give the feeling of p. This happens constantly, in many variations, and all of it impacts samples tremendously.
Another thing I've often noticed in relation to dynamics - listen to a line in a live orchestra marked ff. You would naturally think, "well, I must use all ff samples." No! Because those samples were recorded with a nearly obsessive focus on the part of the player and conductor to get a "pure" ff. This NEVER happens in a live situation. There are constant little dim, cresc, mf, fff, f, variations. So if you use all those perfect ff samples, it is totally artificial sounding.
I guess this is a little off topic of questions of pure sound and reverb, etc., but I think this dynamic question affects the overall impression of the sound of the orchestra more than people generally imagine. If you are hearing instruments at a uniform level which contradicts their natural imbalance, it is as if you are no longer in a natural envorionment. so the most perfect reverb in the world will not help at all. And you might conclude that incorporating these "flaws" - not ony in the sense of dynamic range and expressive and unwritten variations, but also extreme mis-timing, even out-of-tune playing - are the entire basis of natural sounding use of samples.
Another aspect of this is in timbral variation of dynamics - in a live orchestra, even if there is a general mf, a soloistic line in the flute might be played at a near-forte, rather than a p as marked in the score, simply IN ORDER TO BE HEARD. And yet it is played delicately, to give the feeling of p. This happens constantly, in many variations, and all of it impacts samples tremendously.
Another thing I've often noticed in relation to dynamics - listen to a line in a live orchestra marked ff. You would naturally think, "well, I must use all ff samples." No! Because those samples were recorded with a nearly obsessive focus on the part of the player and conductor to get a "pure" ff. This NEVER happens in a live situation. There are constant little dim, cresc, mf, fff, f, variations. So if you use all those perfect ff samples, it is totally artificial sounding.
I guess this is a little off topic of questions of pure sound and reverb, etc., but I think this dynamic question affects the overall impression of the sound of the orchestra more than people generally imagine. If you are hearing instruments at a uniform level which contradicts their natural imbalance, it is as if you are no longer in a natural envorionment. so the most perfect reverb in the world will not help at all. And you might conclude that incorporating these "flaws" - not ony in the sense of dynamic range and expressive and unwritten variations, but also extreme mis-timing, even out-of-tune playing - are the entire basis of natural sounding use of samples.