Upon reading the initial announcement, I was cautiously optimistic. After seeing the CES demo, though, I think it will be a load of fun for kids as is.

Ultimately, though, I think how well it will do will be heavily impacted by how hackable it is. It will eventually be hacked, of that I have no doubt - it's just a matter of how easy and how cheap it is to do. If they used common standards for NFC & the data contained onboard the tags, we might see these used pretty regularly in MOCs - imagine a train layout that plays different sounds and displays different lights as a train moves through a town, GBC modules that react to modified balls with tags in them, or MOCs that add simple movement as a means of triggering custom nature sounds.