What do you do with a Blacklist full?

[SerLuke]

Then they should be asking the developers, not making a post about it in general discussion. This is a place where players come to... discuss things. Last I checked, none of us will be able to give them additional blacklist space. The only thing we can do is offer advice about how THEY can handle the problem differently.

Actually the in game notes for the Suggest a Feature section in Active Help recommend posting suggestions to the FFXIV General Discussion section of the forums.