This is the first I've heard of it and I think it's a fabulous idea!
So I checked it out and it certainly seems like they chose a variety of styles - and that they're trying to be representative of different time periods, and when you do that some of the images may look out of style. But maybe that affected their choices; these could be the less "dated" looking ones? I'm no SU expert though (I've only stamped since 2007).
I am guessing the oval is the new one? Not crazy about that - I think the new one should be really current-looking and it isn't.
I will say that recently I've found in Stamper's Sampler and Take Ten that some of the most stylish and current cards feature old, old SU stamps. So I guess "dated" is in the eye of the beholder
P.S. I saw the video for the "Dude" kit - it was really cute.