Keywords "normal enemies"
You do realize if you don't do the side quests you have no idea what happens to pulse? You go down to pulse and they explain nothing. You go to Oerba and they don't even tell you that Fang was the one that cause the village's destruction, and essentially caused the entire war of transgression. The entire backstory for Bartandalus is in the datalogs, so if you don't read those, you have no idea why Bartandalus is doing this. Hell I was arguing with my friend; who thought Bartandalus was just some Fal'Cie who wanted to kill people because that's what he does. Until me and his brother had to explain to him about Etro and the door to the maker. This is not good story telling AT ALL. This is an example of what you do wrong in story telling. You never had this issue in FFX because all the backstory was explained in dialogue or with that Maechen character, explaining every area and its backstory. There's no encyclopedia for FFX because its not needed. FF XIII's story doesn't make any sense without the datalogs.
Final Fantasy XIII's dialogue is atrocious. Every character said the same shit over and over again right near to the end of the game. FFX's dialogue, while started the anime trend, was well done. Seeing Yuna break down a little past the midpoint of the game cause she didn't want to die, but kept on a facade to give strength to others, Wakka's character arc was amazing, going from the al bhed hater because of what happened to Chappu. Lulu's involvement with Chappu and Wakka. Auron's entire backstory. Everything was actually written well. The most development I saw in FFX happened at two parts of the game; Chapter 7 and 8 (Which was really well done). That's two chapters out of 13. And even then two of the 5 characters who get developed revert back (Hope freaking out on Pulse was stupid and out of no where considering what happened in Chapter 7 with his father).
Note: I might have the chapters mixed up.
without the logs he's some sort of lower god who doesn't like the society he's responsible for. so he causes trouble to create chaos which at some point makes an upper god, who's left the world in the past, reappear who then hopefully creates an new, better society. With the logs he's the exact same thing with history. It's not that his doing is totally pointless without the logs. you just get more background info about him and the world in general. i think the logs were a compromise of being cost effective and putting as much story content as possible in there.
now regarding character development: lightning went for an only caring for herself and serah to an caring for others as well character. both lightning and hope overcome their hate for snow. vanille deals with her guilt for causing all this... and so on. i certainly don't see why ffx should be so much better than this.
Bartandalus cares for his society; he just wants to see the maker more. At no point in the game does Bartandalus explain that he's doing this to see the maker. At no point do they explain that he needs the spirits (Those things floating around in Oerba) to open the door to Etro. At no point out of the data logs is this stuff explained.
Lightning did change, Serah didn't change cause she wasn't in the game much. Snow didn't change. Fang's only shred of character development was in a sidequest with Zazh. Hope somewhat changed, but not much, they kinda thew him away after you unlock Alexander. Vanille didn't change, you just got her backstory. So where was the character development again? Like I agree you that characters got a bit, which is what chapter 7 and 8 were (Which as I stated before, was extremely well done), but after that everyone but lightning reverts back until you get near the end and everyone's like "Let's save Cocoon... by destroying Cocoon!" cause you know, that made sense.