We’ve found cruise ship enjoyment is inversely proportional to the ship’s capacity and how close to that the sailing is.
iow - Sold out ships will always be far less enjoyable.
Another concern is the term ‘sold out’ A 4000 passenger ship can be at 4000 adults and next to zero kids or. A 4000 cap ship can have 4000 adults and 2000 kids. Same ship, just different definition.
Don’t sail at vacation time.
Also the longer the itinerary the fewer working folks on the ship. So go for 8 or more days and you get an older, more enjoyable crowd. We like the 14 day ones best.
Also of note — summer of 2022 many ships got good reviews. Still covid crap and test. Come November 2022 and on, into Christmas, etc every ship tended to be sold out with max kids. Virtually all reviews are negative.
Moving forward I expect every money losing cruise line will pack their ships, no matter what it takes.
And NO cruise line will tell you ‘how sold out they are on any sailing’