Just a few notes from me. Not much on the main point of what will happen within the major plot, but still interesting things.
First off, I agree with Drayker. Tanzan Cove is now almost completely dive-able, and Simon had said that "Whatever is left of her resides at the bottom of the lake" (Or something similar). Possible that it could lead to a side-quest to recover her/her remains (I fully hope that it will be possible to recover her alive. Possibly a Wailord swallowed her, leading you to have to battle a pod of level 80(or up) Wailords to recover her. Even though it is just a vague hope)
Next, Titania is actually a Fairy Tale reference (Who is her ---> http://fairytail.wikia.com/wiki/Erza_Scarlet). To back this up, the mansion's name is the Fiore Mansion (Fiore Kingdom). She even has really bright red hair. She is fiercely loyal to whoever she is allied with, and it is really really doubtful that she would betray anyone on her side. She is also really really powerful, despite sometimes being too serious.
I also noticed various, seemingly new (Or I just didn't realize them before), places where you will be able to use rockslide/surf throughout the map, leading to items or new areas.