I contacted Royal about what was included - here's the reply I received. I'm sailing Independence in a month so can report back our experience.
Yes, Izumi Hibachi is now part of the Unlimited Dining Package, subject to availability. I hope you will enjoy all the benefits of this Dining Package! Please let us know if you have any questions about this or if we can help in any other way.
We are delighted that you have purchased our Unlimited Dining Package so that you can enjoy specialty dining at discounted rates! Izumi Sushi, Playmakers Sports Bar & Arcade, and Fish & Ships are a la carte options, and as you may know, your Unlimited Dining Package provides a $35 credit towards your food purchases in those venues. On the Independence of the Seas, Johnny Rockets has a cover charge of $9.95 per person, and you may use your Unlimited Dining Package there. Regrettably, Vintages is not considered a specialty dining venue for purposes of our dining packages, and we are very sorry for any disappointment this may cause.