The reason it doesn't win is because it's not the best program for most people. I like GP, but I don't think it's even close to the best program. The people that vote for these things vote for the programs they find they can take advantage of. If they don't take advantage of GP, they won't vote for it.
The fact that Hyatt has had the smallest number of properties compared to Hilton, Marriott and Starwood and even Priority Club affiliated properties means less people stay at Hyatt properties and there's a smaller universe of potential voters for the program.
That said, FFN has always been overlooked for best promo. But the reasons are the same (smaller universe of eligible properties means less people can take advantage of the promo and thus it gets less votes) even though it merits getting that award IMO.
-David