We've done as many of the Royal class ships as the others and for our money the most important thing is the food, so we'll be staying with the Royal class (and newer).
Yes, they do have problems with noise in the Piazza but we work around it without much effort and still get to experience the newer options that class offers.
Itineraries don't mean that much as we sail the Caribbean most times with the ship being our destination.
As you noticed, many things have changed over the years and not for the better. Fettuccine Alfredo used to be great, now it's just passable under the guise of being more healthy.
Even though you would be slightly earlier they still would have seated you.
From what I've seen the times are only approximate, especially the earlier ones.
Sure, things can happen to new ships just like the old ones but considering the age of the older Princess ships, I'll take my chances with the newer ones. Been there, done that many times to learn it for myself.
That's why I get rid of my car every few years. Even with maintenance, the older they are the more that goes wrong.
Yes, it can happen on any ship at any time but considering the age of those older ships, it more likely to occur as well as plumbing blockages and overall appearances such as rust, sagging mattresses, wear and tear, etc.