Fairly detailed proposals for being able to exchange any currency for another have been put forward already. At it's extreme end, a bajillion prayer beads can be traded up for astral shards. It's long overdue and ensures that everything has some notion of value. Especially true in the city that was founded on trade and barter.
Benefits everyone from casuals to hardcores. There will be inevitable disagreements on the exact exchange rates between different commodities, but you only need to take a look into a dozen or so veteran (non-duping) players bags to see what collectables and ingredients they have acquired over the years.