Well, one thing I have to say that stood out for me in chapter 648 was Shirahoshi. In less than five minutes she went from the cowardly girl with a brave heart to a total pimp. She had creatures the size of the Dallas stadium instantly acknowledge her as their queen. As Neptune said, "It's finally awakened. The power with the potential to destroy the world." I'm waiting for the day when Shirahoshi realizes just what power state she is in. I don't mean destroy the world power, I mean purely domestic. Here's a little scene portraying just that.
Neptune: Shirahoshi, clean your room before you go out.
Shirahoshi: I'll get around to it later, possibly.
Neptune: No, clean your room, now. You can't go out until you-
Sea Kings appear behind Shirahoshi.
Shirahoshi (with the most sinister look imaginable in her eyes, sounding kind of like Yami Marik from Yu-gi-oh! for the rest of the skit): You really have no idea what you're f#%king with here, do you?
Neptune: But the rules your mother and I layed out for you and your brothers as kids say that-
Shirahoshi: Screw the rules, I have Sea Kings!
Neptune: On second thought, I'll get the Minister of the Right to do it.
Shirahoshi: That's more like it, Santa Claus. I'm going to the mall, so how 'bout them credit cards, pops?
Neptune: Ok, here's my Ryugu Express card.
Shirahoshi (snaps her fingers): Wugwug protests otherwise.
Neptune: Who's Wugwug?
Neptune (looks behind to see a Sea King staring him down): Oh, that's Wugwug. As I was saying, you should take my whole wallet, and here's the check book while I'm thinking about it.
Shirahoshi: That's more like it. I'm going now. This whole place had better be spotless by the time I get back. Au revoir, chucklenuts. Posse, come! Let's fuck shit up.
She leaves, with five Sea Kings following her.
And Neptune becomes the bitch in the father-daughter relationship. I don't know about you, but I can see it going to her head and coming to a boil in about a month. If she had tapped into this power as a child, Otohime wouldn't have needed all those petitions. All they have to do is show up at Mariejois on the back of a Sea King and go "Now, about those Reverie tickets..." and we could have skipped half the flashback in this arc. She doesn't need to be daddy's little girl, or even royalty, to get what she wants, because she has Sea Kings. Just like paper beats rock, Sea King beats rules.