I just googled prior years' Starbucks cups. I'm now starting to think that most of this was rooted in keeping costs down. When I used to work in the grocery store, we saw this kind of thing happening all the time, especially once the economy tanked. Tropicana was the worst. Every shade of color you add to anything increases its cost. Even if it's the same amount of ink, more colors equals more expensive. Looking at Starbuck's holiday cups over the years (2010 must have cost a fortune), you can see they've been working toward a simpler/cheaper design pretty much since they started. These cups have to be a designed and custom printed each season, that alone would make them more expensive, start adding in all the flare and you're into some serious coin.
Starbucks sells 4,000,000 cups of coffee per day. Assuming five weeks of the holiday promotion (might even be longer than that), Starbucks needs to print 140,000,000 of these special addition cups. If Starbucks can save $0.03 per cup by not having extra colors (Tropicana saved almost $0.09 per carton by simplifying their color scheme), that's an extra $4,200,000 some hire ups can stick in their pockets.
People hated the new Tropicana cartons because it made it too hard to differentiate which flavor was which.