I think I'm just annoyed at how perfect this royal family is in comparison to others. Otohime is a shining example in a horrible arc but she couldn't keep peace in her country for 800 years. She also couldn't fight in the slightest.
Same with Vivi and her dad. Relatively normal people who have to rely on others. That makes it easy for the audience to relate to them. That and it had novelty on it's side since Vivi's first role in the eyes of the audience was elite mook.
Here I just...they're too unreal. 800 years of peace yet all of them seem capable of fighting(the two create a sort of cognitive dissonance). Doflamingo's plan wasn't that amazing. Even next to Hody's plan(granted Doflamingo wasn't spotted by anybody). In fact he seems to be doing a lot of things that have no point. Violet kinda reminds me of Vivi since she was a "villain" first but that lasted what half a chapter?
Basically this feels like a lesser Alabasta in terms of royalty.