Right now it's supposed to accommodate all of the Reserve Collection mini suites and the Reserve Cabana cabins.
In the future it will be for the mini suites (which are now Sanctuary Collection mini suites) and the 16 Deluxe Balcony cabins.
BUT, and it's a big problem, all of the Reserve Cabana cabins that booked before April 23 still get Reserve dining grandfathered in AND it seems that immediately the 16 Deluxe balcony cabins also get the Reserve dining. So for about the next year there will be a massive overcrowding problem (which people have reported has already happened.)
I don't really see them combining the dining rooms. We're in one of the mini suites so I have no skin in this game but, had I booked a suite, at thousands more, I'd be pretty peeved that the dining was combined.