My apologies if I misunderstood you. I do disagree that such things are considered just small details though. In my experience, those details will make or break the entire performance. No one wants to listen to a live performance of what sounds like a midi track.

I do agree western music notation is very flawed, but creating a kind of notation that properly represents those things is nearly impossible. People have been trying for centuries, but so far the current form of notation is the best we can come up with.

Because of its limitations, musicians very often treat sheet music as a general guide, and deviate from it whenever they feel it is necessary.