When will SE let us send mail / items between characters?

[ispano]

That's not the problem. They first need to make it so that you can't put untradable items into a shared account-side storage, which is probably what they're trying to do first before anything else. This is the main reason why RMTs make alts, so they can use account-wide storage to transfer untradable items. TERA has transferrable untradable items, but only in shared bank.

That system is already in place for FC chests. Has been from the start.