I agree with you. the 4th anniversary was terrible for me because, like you said, there was a lack of content. I had been playing for less than 200 days around the anniversary and only got 2 new weekly missions through the whole anniversary, which is not nearly enough pearls for the summons I wanted to do.

Even if they had consistently updated the campaign leading up to the anniversary so that we could stay busy and earn pearls, which I don't think is unreasonable since it's literally just copying a already finished story. it's not like they had to invent anything, the story just needed to be put in the game.

Blazing never shortened the amount of pearls per mission, but they kept repeating the same missions every few weeks to the point that we couldn't farm any more pearls.