Regarding the whole "FFX was linear and nobody had a problem with that, and it made the characters lovely" - I know this is slightly off topic but I hated the way FFX was linear and I couldn't stand Tidus, Yuna or Wakka. The other three characters were alright, but in FFX it wasn't a story about them, it was a story about Tidus, and he was the worst character of the lot.
FFXIII does it differently. The characters are awesome, unlike FFX. And the linearity is much more forced - (SPOILER)you're on the run, why would you be going back? It wouldn't make sense. And it's not as linear, for me - at least, not mapwise. I think that if we didn't have the minimap in the top-right corner, people wouldn't notice how linear the maps are. I mean, really - all the "secret" item spots are right there on the map, it makes for little exploration effort on our behalf. :p
So far, for me, FFXIII is untold amounts better than FFX in almost every way - the exception being sidequests, but I'm reserving judgement on that end as I've only just got to (SPOILER)Pulse, where the sidequests begin.