I think the premium suites on most lines are gone far ahead of time. Fourteen years ago, we went on our first cruise (RCCL sister ship to Majesty, I just went blank), Southern Caribbean out of San Juan. We requested "B" category a year out, had to waitlist; it never cleared and we sailed in a "C". We were able to snag a "B" on Legend of the Seas for Panama Canal, and talked to a lot of people who had waitlisted for that category months out and wished we had canceled.
We've tried for premium suites on Navigator, and had to waitlist until final payment date; some cleared, some didn't. With the Navigator Suites being directly under the pool (except for that one new one), the demand for Grand and Master seems major. A travel agent who blocked those off would need to be very sure of his/her clientele. When the 60% off sale hit, we signed up for a "normal suite" on deck 6, so we may very well step out of the competition for the larger suites. This time, we just want to recreate the cruise we took in February, because there's been so much trauma in our family since we got home.