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.
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.