Not sure about the size of the rooms, but Seashore lists four MDR's (more than Seashore which had two buffets but often closed one to serve as location for seating for evening dining). It does include the larger two Central Park, and Tribecca, and the somewhat smaller 5th Avenue, and Manhattan restaurants.). They weren't all open when we sailed for two weeks earlier this year, and we were quite happy in YC so didn't try moving.
On the elevator situation, you mentioned that MSC disabled the system. In this case, the override system was never installed. MSC put in a new system for control, where all passengers enter the floor they want, and and are then notified what car to get on. Our butler told us that the system is designed to give preference to selection of YC floors within the front elevator banks, but it didn't really match up to our experience. I must say, I did like the system in that it reduced people rushing to get on any car that opened.
