For me, FF13 just fits well to the J-RPG genre - it's different from W-RPGs in many ways (though not that many as previous installments) and I'm probably one of the few people who didn't mind the linearity. What really disappointed me was the Crystarium - it offers no real choices to develop you characters to suit your needs! It's just a crippled offspring of FFX's Sphere Grid.

And yes, I did miss the world map, but Gran Pulse made a good just substituting that. In my opinion, world map in previous Final Fantasies only provided an illusion of freedom - you more often than not were restricted where you can go early in the game (either by strong creatures you can't kill without insane grinding or just by natural obstacles like mountains) and by the end, you always had some means of quicker movement (airship, chocobo, teleports, ...).