TL;DR: make separate vaults for different characters; swap items between your characters via the Postmaster. I am not a huge fan of shared vault. 20 slots for gear for all 3 characters does not seem like much. Granted, I am not utilizing all of the vaults space yet, but I can see myself running out of it pretty quick with all the legendaries and exotics that are laying around in piles all over the game world (hahaha, get it? That was a joke. [b]:-([/b] ). A vault locked to a specific character would be amazing. And as for swapping items, we can do it through the postmaster, since he is pretty much useless most of the time (he gives you your rewards for completing public events and ranking up, the rest of the time he is useless). You decoded legendary or exotic engram with your Titan but got an exotic for a Warlock (hahaha, another joke! I am on fire! Cryptarch is a colorblind, sadistic piece of crap, who will shit on your dreams). Just run up to postmaster (or even the Special Orders lady), leave the item, switch to your Warlock, go to the postmaster, and get your item. Then you can put it in your vault, that's locked to a specific character, and not take up your Titan space with your Warlock bullshit.