You know what would be pretty cool? If instead of having Grey Knights we could have a unit of Librarian codiciers!
Think about it, what the grey knights have in abilities and in equipment the Librarians also have it. They could replace grey knights with them and so make the Blood Ravens even fluffier or just represent the psychic force of your chapter in multiplayer.
They are similar in which; They use a devastating psychic attack, they have force weapons and they could have furious charge as a result of their psychic nature.
what do you think?