R3 played the Haydn London symphony today, and I was reminded why I love it so much. Masterful, majestic writing indeed. I am now having a very odd thought, after Ian H's reminder about orchestra sizes, and a conversation I had yesterday about the rugby, and in particular George North. One variant of that is the perennial question of whether the evil sods who formed the Pooler front row would heva survived, playing under the old Laws, versus a modern front row.
The musical part of my reverie was to wonder how someone like Haydn, or Bach senior, would have reacted when confronted with experiencing a modern orchestra playing, say, Mahler's 7th, and then being handed the keys to the conductor's box (ITSWIM).
Both Wagner and Mahler, at least, along with Sousa and Saxe, created New Toyz, or, especially Mahler, came up with new ways of using existing ones (horns in Mahler 2nd, bass strings in Beethoven 6th). Look at how the greats reacted when pianos arrived and then developed as an example.