1. Discussing personality would mean discussing the massive changes that the characters undergo throughout the journey, and likely bring up a ton of spoiler content to verify or discuss points. Or we'd get discussions like "I wish [Character A] was more [Trait B]" or "Why is [Character C] so [Trait D]". The response to both of those would be spoiler material, so those of us who've played it would be dancing on our seats but not actually posting for fear of spoiling people.

2. Every character design is related to an asterisk, which means that it relates to an individual you fight. Early knowledge of these designs spoils what the jobs are, and can spoil who holds them, or how the fights play out.

3. Abilities are almost all used by bosses, and we get the same problem as above. I can't even really discuss why strategies are spoilleriffic, since I'm pretty sure you aren't nearly far enough in the game to talk about it. I mean, sure, we could talk about the early bosses, but they're not that difficult anyway (and even then, we can risk spoiling people for fights, as above). But the fights that require deep strategy come in the last few chapters, and even listing what you're facing would be massive, massive spoilers, and would at least slightly dampen some of the greatest moments the game has going for it.