I have no issue with the Concierge lunch on embarkation day. I agree that using an unused space for that is more efficient. I cruise on other lines that have a loyalty program lunch available for returning cruisers that do just that.
What I have issue with is separated dining rooms based on category of rooms booked. That's how Cunard does it. It does have the "separation of classes" feel. Much like the original set up of the Concierge rooms on the Dream. They had gates into the area where the concierge rooms were. That didn't last long as many people expressed negative views of the "we're better than you" attitude that projected.
I don't begrudge anyone paying for Concierge perks, as long as the perks are something that's included as being booked in a Concierge room. Character meets, meeting the Captain, private lounge, whatever.
DCL has a similar opportunity for returning cruisers in the Gold & Platinum cruiser reception that's available to everyone, once they've cruised DCL. Same with the opportunity to book things earlier the higher
castaway club level you achieve. Again, that's an opportunity available to everyone, once they start cruising DCL.
I'm sorry if some take offense at my opinion, but I've a great believer in everyone being equal. Designing a ship with a dining room that's only available to a specific class of stateroom, isn't equal. Palo & Remy - while there is limited space (not an unusual situation in any fine dining venue), and higher level Castaway Club members could fill all available space, it doesn't always happen that way. We booked Palo on our very first cruise. And every cruise since then.