Cruized twice - first trip (4 nights) got STUCK with the latest late seating rotation and frankly didn't like it at all. We just don't eat dinner that late.
During onboard rebooking for cruise #2 I nicely but firmly insisted that it would be a dealbreaker if I didn't get main seating and amazingly the onboard agent was able to override something with somebody and I received confirmation of main seating for the second cruise. We enjoyed our main dining time very much on cruise #2. (Note: There was a family next to us and their young son fell deeply asleep at Main dining just about every night.)
Rebooked on board for cruise #3 and was told late seating only. Basically got a "too bad" attitude about my request for main seating and it being a requirement for our purchase. Got home and cancelled cruise #3. For the amount of money that I am spending to cruise on
DCL, I am not willing to compromise my seating preference time. I wasn't going to leave my seating time to chance, after I had paid in full, to hope that upon boarding maybe they could or would switch us to main seating.
Just my personal position that I wouldn't compromise on my dinner seating time. We would not have been happy cruising again with late seating, especially on a 7 night cruise. We survived late seating on a 4 night, but it was not for us.
Again, it comes down to being satisfied with every aspect of my very expensive DCL vacation. To us, the dining time is a very large important part of the trip and non-negotiable.