My apologies if this has already been suggested, but I'd love to be able to add friends who are currently offline. Perhaps a button could be added to peoples' profiles and they would get the friend invite the next time they log in.
I've got friends who are on erratically or at odd times so I never know when to look for them. If I could add them when they are offline and they accept the friendship, then I'd get notification when they come on.
Thanks for listening,
Fuzzy