IMO it doesn't matter if the story only goes in one direction. The problem I have with for example FFX was that it felt like riding a train. You know I wanna explore the world how I want but I'm stuck on these stupid tracks. It's like comparing trains to airplanes...
It's not that I particularly dislike linear games. I just prefer open worlds and I were looking forward to exploring the world of FFXIII so I'm a bit disappointed.