Now to be honest about it, those photographers have never seemed to be a delay to me. I guess for about our first 20 cruises we always stopped for that boarding picture. I have a trunk full of them. But since the checkin process at the desk takes several minutes, and people feed off it fairly randomly, it seems to give the photogs their 30 seconds in a fairly regular flow.
These days, we just wave at them and pass right by. Most places are so arranged that it is possible. If they did put it in a doorway, and a line was forming -- well, I am the kind of guy who would just brush right past and walk right through their picture. I would probably be polite enough to say, "Excuse me." But businesses that take advantage of my sense of etiquette to try to sell me something get short shrift from me. I certainly don't wait in line for something I don't want.
One of the best boarding experiences we had was in LA, on a NCL "fam" cruise to nowhere for travel professionals. Evidentally US Customs delayed disembarkation, and there were a thousand people waiting to go on board. We had a large room to wait in, plenty of comfortable chairs, and coffee, juice and cookie service kept well maintained. Even more important, the staff circulated with accurate information about the situation (even when it was "we're not sure") and there was a plan ready to move those people in small groups when boarding was ready to begin.
OTOH one of the worst was in Montreal. There was a very large cruise terminal, but ONE security scanner was set up at the very entrance so that a long line formed outside in the cold windy Canadian weather, with no chairs and little shelter. It is largely a matter of logistics, how well the cruise line plans to use the existing facilities. Somehow I feel that most of the time it is left to marketing people, to the purser who is largely a bean counter, or worse to the HR people who try to save money on temporary staff. There are many people trained in logistics of crowd control. They need to hire consultants from a major sports venue or Disneyland. A whole lot more than 3000 people arrive for any pro football game and don't have to stand in line for hours.
Long ago I purchased a seat cane so that I have a place to sit down in situations like that (and also when DW decides to go shopping!)
As far as preparing the ship between sailings, it really is only the cabin stewards who have a tough time there. Since the dining room is sparsely used, if at all, staffing the buffet should not really be a problem. Once again it is a matter of logistics and manpower usage. The stewards need to do the job they are trained to do, but other staff could easily be assigned to keeping supplies moving, towels where they need to be, vacuums plugged in and many things that would speed up the process. Once again it is a matter of looking beyond the way they used to do it.
It is strange that some ships seem to do it very well but others in the same line can't manage it. This points to energetic and innovative officers at the ship level but brings up the question of what is happening from corporate.
Of course, we all know the three biggest lies in the English language. Number three is, "The check's in the mail." Number two is, "My wife doesn't understand me." But the NUMBER ONE LIE is, "Hi there, I'm from Headquarters, I'm here to help you."