Early seating on Carnival is 6:00 PM, late is 8:15 PM while Princess is 5:30 and 7:45, Holland America is 5:45 and 8:00. No question, when you have that large of group it is best to nail down a table and time if possible. However, most passengers nowadays prefer open seating, anytime between 5:15 until 10:00, unfortunately, both Princess and HAL are not offering commensurate dining room space for the open seating (anytime) therefore it is a little more rushed than in the traditional restaurant(s).
I glean that all 10 or 11 of the majors are running into this as well, meaning less staff and poorer quality cuisine in their main dining rooms, all the way around.
I believe Princess has now cut back so far they can't get the limited staff to adjust anymore, that I also believe is what is going to happen to all of them. Six would be better than 5:30 or 5:45 for us, although we long ago got away from traditional when the cruise lines started offering open seating. Reasons we don't like traditional is: 1. You are locked into eating at those times only. The late is way too late for us anymore and the early often coincides with the ship's sail away on port days. One of my favorite likes when sailing is the sail away, so I don't want to be down in the dining room feeding my face when I could be on deck taking every thing in. Also, there are many other events and things happening that conflict with traditional dining times at times, for us anyway, so it is awkward to have to keep letting the restaurant staff know you won't be there for dinner. 2. Some of our voyages have been months in length, it used to be hard to get a table for two in traditional seating, therefore you had to go with the luck of the draw in that you were seated with sometimes two or three other couples. If you didn't like them, tough, you were stuck with them for the length of the voyage. Now, we were fortunate and never ran into someone we really didn't care for, except once or twice, but witnessed a lot of horror situations. So we started getting a table for two before our luck ran out. But then, along came anytime dining and that was great.
Unfortunately, that option is not so hot anymore as well. Bummer. In summary, it looks to me like a pay extra for dining in the specialty restaurants or use the buffet area when you don't want to shell out unless the MDR works out for that cruise. Sometimes the buffet areas can be quite good, unfortunately, if they are busy, some of them are terribly noisy.