when I first started fishing the park not too long ago, say 8 years, I was happy to catch a keeper. Now I expect to catch a keeper everytime. I have gotten more experience therefore better, but I do think the fish have gotten bigger (maybe just in certain places I fish). Not scientific mind you, just from observation. I remember reading books that would say any rainbow over 8" is a good one. I've seen a few pushing 10" or so.
on a seperate note concerning acidic waters.
Pike County IN has been a mining region for years. A small river was dead for 70/80 years from acid mine drainage. It flowed orange. In the 90's serious reclamation was undertaken and river is coming back to life; plant life, dragonflies, spotted bass. However it is still pretty invertabrate deficient compared to other local waters. Big fish (piscovores) come in and hang out but the base invertabrates are harder to establish therefore the small sunfish aren't too prevelant. Sounds like the smokies just with warmwater.