Okay, so I'm up to the final boss (just need to get my house in order before I beat him - tried just now and Instant Death is not my vibe), and am really trying to understand the gripes that people had with XIII.
1. Vanille is annoying
Seriously? Okay, she's not going to win the award for the most desirable person in the entire world, but reviewers really made her sound like the most irritating character in the entire world. Not saying she's a great character either, but people went overboard with her (and to be honest, I found Hope the most Tidus whiney, Squall emo and Vaan pointless character for the first bit of the game - although the development worked for him).
2. Linearity/Lack of Towns etc
Fair enough, for most of the game, you are walking down a straight track. And there aren't many side-quests (and I love side-quests). But, I started playing this game on Thursday evening and am yet to be bored. I think that there was an over-correction from the vastness of XII's world causing the story to lose momentum, but I don't think it was that troublesome. Would I have liked to see towns (like in previous FFs) and side-quests that involved stuff besides hit the monster? Yes, I would have. I am still trying to find out why Gran Pulse is EMPTY of humans (!!!!!!!!), but the designers really should have done a bit more with that world. But, I don't think this is as big a flaw as people made it out to be.