Skellige is full of question marks and I'm lvl 25 debating if I should finish all my question marks first or push the story line (collecting brothers in arms currently for Kaer Morhen).
I should set up Chrome Remote Desktop.
There is a bunch of cool stuff on the land POIs, but any POIs in water and you're just diving for trash. I finished like 80% of those Skellige POIs before I was finally honest with myself.
Mood and ambiance wise though, Skellige was my favorite part of the base game by far.