I can entertain the possibility that Woodley's late opponents would beat some of GSPs wins. And a lot of people seem to put a lot of weight into the downslope of some fighters after their title shots. But when you look at GSP's fights in context, he has a far better resume that Woodley.
Bisping - UFC MW champion
Hendricks - would go on to become UFC WW champ
Nick Diaz - Strikeforce and WEC WW champ
Condit - interim UFC WW champ, WEC WW champ
Shields - win over Woodley, Strikeforce MW champ, EliteXC WW champ
Koscheck - never quite made it to the top, but with different luck he could have; I had him winning over Hendricks
Hardy - OK, I'll give you this one
Alves - was a monster at the time and was coming off beatdowns of Koscheck, Hughes and Parisyan
Penn - UFC LW and WW champ, won 5 or 6 title fights in UFC alone
Fitch - had won something like 16 in a row prior to fighting GSP, 8 in the UFC, would go on to become WSOF/PFL WW champ even late in his career
Serra - TUF winner and UFC WW champ
Hughes - UFC WW champ, won 9 title fights in UFC
Sherk - UFC LW champ and WW title contender
GSP has been the winner in something like 12 or 13 UFC title fights. I don't think Tyron has even had that many fights in the UFC yet.