I don't know how they choose which model to make into the next exclusive.
Spyderco doesn't choose what model to make into the next exclusive. Dealer exclusives are asked for by the dealer, believe it or not
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On a slight aside, your post got me thinking about comparing sprints to exclusives. In 2011, there were four sprints of Golden made models, the CF/S90v and grayG10/20cp PM2's, brown G10/XHP Military, and M2 in B75P. This year there was only one, the orange Dodo. In total, there were six sprints in 2011 and four this year, so put another way, 60% of 2011 sprints were from Golden compared to 25% this year.
I'm not sure if all the exclusives from 2011 are listed on spyderco.com/exclusives, but I do see them as far back as March so possibly. Suppose they all are. There are six 2011 exclusives listed and 10 this year. Two of the 2011 exclusives are Golden made, and five are in 2012, meaning ~33% of 2011 and 50% of 2012 exclusives were made in Golden.
Exclusives and sprints combined give 12 for 2011 and 14 for 2012. Altogether, 50% of exclusives+sprints in 2011 were Golden made, ~42% for 2012, and it's even with six a piece per year.
Not that two years provides much towards predicting trends, but there is that constant of six Golden sprints+exclusives per year. We know two now, the Yo2 and M2 XL, so hopefully there will be four more. Perhaps I'm being optimistic, but potentially with four more unknown and a Military sprint or exclusive every year since 2005, it seems like there's a good chance of another in 2013.