An update: I've returned to Sprinkles a few more times expecting them to magically get better...
Not so much.
I've had the opportunity to try a few fruit flavors since I've been able to get up to Scottsdale in the middle of the day. The Strawberry Cupcake? Meh. Not so hot. Very light on the fruitiness, almost like an afterthought. The Orange Cupcake? A little better, more like a creamsicle cupcake with all the vanilla going on.
The Chocolate Marshmallow is a different story. This is probably my favorite cupcake out of them all (Thanks to the injection of marshmallow cream in the center! Helps with the dryness of the cake...), but only one variety out of the 20-odd they serve that I truly like? Not worth it at all.
Again, I like my scratch cupcakes better, even my sister's gussied up box mix cupcakes are better than these.