Most sandboxes have a storyline that you can choose to follow, I don't see how it would detriment the game.
Again no you misunderstand, I dont mind the campaign. In warband if you play sandbox, you craft your own story, you do what you want. Unlike in viking invasion campaign where they basically give you a story to follow. You can choose to follow it if you want to but its still annoying. I feel a lot better when i dont have a random quest for me to find some random ass family member making me feel guilty for not following the storyline.
EDIT: making myself a little more clear