Blacklists are starting to get huge. Here's something useful that can help you determine who to unban if you run out of room.
Go to Lodestone, login to your character, then go to the friends list. In the friends page, there's a tab for blacklist. You can click over there and see portraits of the people you've banned. You can also click into them and see if they've played it all, or if they're just lvl 1-5. In mine, I can see that most of them are using the default hume male model, and a few are using very slightly altered miqo'te female models. The ones that aren't using those models, if they have some high level classes, they might be people with hacked accounts who may or may not have those accounts back.
I've noticed that there's a whole lot of legacy characters as well that haven't leveled up since 1.0, so you can look at their sixth era stats to see if that's the case.
