Pieces were written based on what the human performers could physically handle. (Speaking of opera here, orchestral is a somewhat different issue.) Unless human anatomy has significantly changed in the last 2-3 centuries, I don't imagine people's vocal chords are yet capable of significantly higher ranges.
And more "brilliance" and "excitement" ... Maybe the piece isn't intended to be that brilliant and exciting, else it would have been written in a higher key.
And more "brilliance" and "excitement" ... Maybe the piece isn't intended to be that brilliant and exciting, else it would have been written in a higher key.