You believe that having an end cut scene and a big boss defeated adds more to what a game has to offer? we disagree , i believe that open world / free roam games only end when you feel the need to make another character and approach things differently .
What i am trying to say is that the journey matters , not arrival to a destination.
I personally want a main quest to follow though, when i get tired of exploration it's nice to get railed for a while and progress the story. It doesn't have to be linear and I don't want the game to end when I finish the main quest.