Depends on the game, but there isnt anything wrong with being linear (destiny is actually really linear you do 1 story mission at a time in order no choice involved) The idea of games not being linear at all has only really taken off in the last 10 years or so. Being linear makes it easier to make a more hand crafted and controlled experience. That being said some of my favorite games have been completely open world. Edit I would also say it usually helps create atmopshere.