(A year late to the party, ha!)
Its too bad the rules for trustlines can't be tweaked to allow the trust of all asset belonging to one issuer. That way, you could create unique assets for games, allow wallets as inventory, trade items on the SDEX.
Because of Jed's background I'll use Magic as an example. You could create an asset for each card type, lands, creatures, artifacts, etc.
Trust the issuer. Any and all cards you acquire could go to your wallet. The interface is a web wallet that allows you to create decks based on cards owned on that private key.
In the current state, you'd have to create a new trustline for each card.