OSU fan here, so obvious I have a bit of a bias.
When it comes down to it, yes Penn State had an impressive year. Going from 2-2 to 11-2 and winning a B10 championship is quite the cinderella year in anybody's book, so I do not want to discredit them whatsoever. That being said, their resume stack up to OSU's this year. Ohio State had 4 top-25 wins, 3 of those were top-10 wins. Penn State had two top-10 wins. I cannot remember if Iowa, or Pitt were ranked when they played each other, so my apologies there, but if they weren't, that would mean OSU and Wisky in the B10 championship are their only resume building wins. When it came to the "eye test", which I despise btw, Penn State won on a blocked kick over OSU and made a huge comeback to beat Wisky. Both impressive, but on the flip side, OSU looked beat down Wisky, beat Michigan in a defensive showdown, and man handled OU.
While reading about the selection process, it was mentioned multiple times that the 4 best teams (based on key wins, eye test, and overall strength of schedule) would make it, and conference championships would be used as tiebreakers, not musts for contention. I think this year was the first year that this was ever even tested, and they set a precedent for moving forward. In the coming years now, it will be interesting to see if the committee holds to this precedent. Guess only time will tell.