Please take a look at this. The way it is now is really painfull.
I have many characters that I play on and when I meet someone that is retarded (racist, troll, ******e, ect..) I usually ignore them. When I meet people that I can do content with or friends that are not in the same guild, they get put on my friendlist.
The problem is that I don't want to write down every friend or ignored guy, and log into every toon to friend/ignore him/her. Please make it like OP says, account wide! Excelent suggestion, 1+!