I'd have a level to link to the story, Having the maps being a ridiculous setting is for me pretty immersion breaking.
I'd say with the direction the story is going, I'd love to go back to Romania to the asylum. It looks like Season 2 will be about 47's past and how the shadow client (or whatever you call the 'villain' of the story, haven't been here in a while) and providence knows about 47.
Another idea would be London to find that girl in the cutscene after Colorado. Maybe add some extra targets to make it more fun. Just the hustle and bustle of London with moving traffic you can use for accidents.