So many things I would have done differently. At least dabbling in playing open-handed, for sure. Trying different setups and different cymbal makers. But most of all I wish I had been more adventurous.
By the time I was in high school, I had already internalized the idea that feel, and being tasteful, and playing to the song, was the thing. Which I still believe! Except -- in my case -- it contributed to my chops never really progressing much since my teen years. And in retrospect I think I would have been better served by taking advantage of my youthful energy -- and all that time I used to have -- to really work on playing harder and faster and more complex, at least in the practice room. I wish I had tried out things I might never have used on the bandstand, and used the impetuosity of youth to find out what I could and couldn't do, and try to eradicate more of the stuff I couldn't (yet) do. I wish I had gone bigger and then pulled back from there, rather than sorta starting small almost right from the beginning.