Sadly, that is boring and short-sighted IMO, and it is not going to tempt repeat passengers.
I’ve done around 40 cruises with P&O - the majority having been on Aurora (altho also been on Oriana, Azura and Victoria) because I love that style of ship and because she went to many different ports over the years.
If she and the other ships in the fleet had stuck to the same itineraries, I doubt I would definitely not have done more than one cruise a year with them and would certainly not have taken the number of cruises over the decades with P&O…..