From someone who hasn't stepped into the Court of Oryx in many moons, these consistent and annoying inventory slot whores we call Runes, are worthless to me. I've attained what I needed when such a reward was necessary to achieve. I think we should be able to exchange these Runes for something. Not sure what, but SOMETHING. Definitely NOT materials!
Trade in T1, T2, or T3 for specific things: The higher the Tier Rune, the better item.
NO to weapons. Either glim-glam, Motes, 3oC, etc...