Pre-pandemic on Celebrity we always cruised Aqua and never had an issue with Blu. Ship was full and never had a wait time. Post-pandemic I have a feeling it has to due with lack of staff. My understanding is that they are limiting seating so that they can ensure those seated are provided with good service. The seating delay, with a pager, allows you to enjoy the rest of the ship, while you wait for your table. Easy way around is, is to head down a half hour early and grab a pager and that way you will be seated at about the time you would like to dine.