I finally made it – I completed all vistas and skill challenges, found all Points of Interests, viewed all Vistas, and got World Completion. Took me “only” three years, but to be fair I took extended breaks.
The reward are two “Gifts of Exploration”, which allow me to craft Legendary weapons. Or would, if I had even remotely enough materials for it, or a precursor. (I did sell off Howl.)
Doing this was actually a lot of fun. Some areas are pretty annoying – Orr, I am looking at you – but was actually quite satisfying to finally get it completed.
So, what’s next? I guess I really should complete the storyline as well. That, though, is a true exercise in patience.