Pennsylvania should have made the list for sure. If you look at the top 50 courses on this site (10+ reviews, which was the standard for last year's site list), here's the breakdown
PA - 6
TX - 6
KY - 5
CA - 5
NC - 3
OR - 3
CO, TN, MI, MN, MO, NY, WI - 2 each
GA, IL, MA, MD, MS, IN, VA, WV - 1 each
TX, KY, CA, NC and OR all made the poll. Of the states with two top courses, MI, MN and WI made the poll. Of the states with one top course, only IL made the poll... For some reason, Iowa is on the poll, despite lacking any top courses.
PA, which is tied with TX for highest number of top-ranked courses misses the poll entirely. And having played all of the top TX courses, and most of the top PA courses, IMHO, the top courses in PA are far better in almost every way than the top courses in TX, or many of the other states listed. Leaving off PA is just a sad injustice.
Personally, I'm voting for NC, because of a combination of good weather, great local clubs, tons of high-level tournaments, and proximity to other great states/courses within roadtrip distance. Charlotte is disc golf mecca as far as I am concerned. And the home grown tour there is another huge bonus, and a rare find. NC wins my vote, hands down, but leaving PA off the list is an insult to all the top-ranked courses and great disc golf folks in that state.