I'm going to come at this from a different angle than most of the blogs so far. One of the places we play is at a game store. The owner makes his living running his store. He emailed me a few weeks back and asked my opinion of these cards. I hadn't heard of them and I am always a sucker for add ons like this. I told him I find them interesting. So for his sake, the friendly neighbor gaming store, I hope they sell a ton.
Am I surprised that WotC went to these kind of cards? Yes, in timing only. I figured they would hitch that wagon onto D&D a long time ago. When gaming with inexperienced gamers, it's sometimes good to have a tangible prop for them to use.
I know Pazio has their Plot Twist cards and the several other decks they have developed and I think they're great.
My favorite were the Whimsy Cards. Very simple cards that players could influence the way the game unfolded. So Fortune Cards are not new. Not by a long shot. I plan on getting a couple booster packs to check them out and go from there.