I led a group trip to Belize on behalf of a dive shop years ago. My feeling from a previous trip had been the same--long trip followed by a boring dive made OK--but just OK--by the bird sanctuary and the other dives there. Most of our diving had been pre-planned, but we had options for longer excursions. When we sat down to plan, I was just about to give my mostly negative opinion of the Blue Hole trip when someone else talked it up like it would be a life-altering experience. I kept my opinion to myself, and the group elected to take that trip.
At the end of our stay, I surveyed the group on their overall experience. The majority (by far) of the group selected the Blue Hole dive as the highlight of the week.
So, I guess it's a case of different strokes for different folks.