I feel like there is still a mountain of shit to learn. No plateau in site. I have had water reports and Pittsburgh water seems pretty good. I treat with campden tabs and use stabilizer in my mash. Works well for me. Not to say that isn't valuable knowledge but it seems like a lot of commercial brewery's do very little to their water.
I'd personally like to get more into cultivating yeast. Huge can of worms there. I have got as far as repitching and that's it. Temp control is a matter of money at this point.