So currently, the rare power discs in each series have a lenticular top to give you an extra feeling of rarity. Well, that will not be the case going forward on the new power disc series.
Why the change? Well if are currently unaware, you could go to your local Disney Infinity retailer and feel out all the packs and you can feel the lenticular discs through the blind pack. Thus not really making it a blind pack, as you can tell whether you are going to get a rare or not.
Disney decided they liked the idea of making them harder to get, and thus took away the lenticular sticker.
Here are some more images from the discs that attendees got at E3