I don't know about sending items to alts, but being able to leave other players messages that aren't on our friendlists would definitely be helpful, Especially your FC members or potential recruits that may not log on at the same time you do.

It'd be nice to be able to send letters/messages regardless. Perhaps not items as I could see the imbalance it may cause; maybe that option can be greyed out or disabled unless that person is on your friendlist.