This might be a long-term thing, but I thought it would be neat if there could be some way to replicate the original organization of D1 cards (e.g. Have the Guardian, Enemies, Activities, Items etc. categories)
It might be a bit tough nowadays what with the old Grimoire being removed from Bungie.net and the Companion App, but hopefully there are enough people to remember how it was.
Edit: Realized this would be the same as http://destiny-grimoire.info/, but I still think it would be handy for navigation.