Two frequent complaints on this forum are: Event rewards feel lackluster, and there are no uses for runes for established late-game players.
Zendikar Expeditions perfectly embodies this problem. Many of the rewards in the reward-ladder are just runes which are near-useless to long-established players, leading to a long grind through a lot of semi-useless rewards to get to a few desirable ones. At the same time these runes are necessary for players on the newer end of the spectum.
To try and fix both of these at one time, I propose that each time a rune-only prize is awarded the game displays a pop-up window with a choice. Get the runes shown as before, or choose a small percentage of that value as mana orbs for crafting; say 5%. It would be easy enough to automate this so that it wouldn’t have to be programmed for each event. A subroutine could be created such that whenever a rune-only reward is offered it is instead replaced with a pop-up menu offering both options.
Even a small amount of mana orbs would be preferable to a semi-useless pile of runes and make these events seem less grindy by having a comparatively worthwhile reward at each step, even if the amount of mana orbs would be small.