Currently, all rune salvage materials are the same (within each rune tier) except common runes only give two possible materials compared to three possible materials from uncommon and higher runes. There is no difference between the outcome of salvaging an uncommon, 1 star, level 1 rune and a legendary, 5 star, level 30 rune. It seems that the rune materials that can be salvaged from runes should scale based on rarity, stars and level.
I'd like to see more rune materials (shards and binders) be awarded for higher rarity and star runes, while higher level runes should award gold (and possibly a chance for essence) in higher increments as the level of the salvaged rune increases. This would significantly ease the blow of having to salvage runes that are now obsolete, but at the time they were crafted required large amounts of materials, gems and gold to craft/tune/upgrade.