How long have you been fishing Pymatuning Lake? If you have been fishing it for any amount of time, for walleye that is, you would know that catching walleyes that were 14.5" was always very common. Why is that do you think? I don't need data from a biologist to figure that one out and neither do you. Due to the heavy pressure for eyes on Pymy, and due to most people fishing it keeping their legal limits is why maybe 1 out of every 15 walleyes caught was always legal. And it will be like that once again. I remember days catching 50 or more fish only to catch a few "keepers". If you increase the size limit to 17", you will merely be increasing the size of what can be kept and eventually the majority of the fish you catch will be 16 to 16.5". In recent years, the bigger fish were more common, however numbers of fish caught down...Less fish, less pressure and fish get a chance to grow with less competition for food to boot...Now do you get it?
IMO, there are only a few things that can be done to increase the chances that fish can grow bigger....1 - NO PRESSURE - to make it C&R ONLY for a few years with continued stocking - WHICH WILL NEVER HAPPEN and 2. LESS TAKE - Cut the creel limits in half along with continued stocking. #1 Partly being the reason why you're seeing more bigger eyes being caught in recent years....Way less pressure due to the walleye fishing being off for a few years due to various reasons (fish kill & Fry not taking well). Increasing the size limit, IMO, is not the answer.
I believe Pymy will be what it used to be in regards to walleye fishing. The numbers are coming back up, the Fry brood are taking well and when you can drift in among 20 other boats like the good 'ol days, you'll be slammin' those 14 and 14.5 inchers left and right with a few 15s thrown in the mix and even a rare 18 to 25". Its inevitable, its called a Put-N-Take fishery!