The more linear a game is the more control the developer has over your experience and the greater attention to detail can be paid to your experience, think Bioshock or Call of Duty 4, both games are linear, but they are engineered to give you the most intense experience possible.
Yet and this is key I think a really good linear game, should never feel linear, you should for the most part be compelled to go the way your supposed to go(or subconsicouly you choose to go that way), and the idea of a large world should be painted, not so much so that we keep hitting invisible walls and say"I guess I can't go there!" but enough that we feel the game isn't on rails, like hallway after hallway with only one door opened at the end. Half-life 2 does a great job of feeling open world without actually being open world.
open world vs. linear is a game choice that amounts to: exploration vs. experience.







