Heirlooms can be upgraded to level 70 in 10.1!
Something about juggling two sets of tokens for various levels and heirloom types is just clunky and weird.
Beside every Timewalking and Heirloom vendor there should just be a Timewalker NPC that can upgrade heirlooms for varying costs.
Either that or the Scabbards and Casings should all be consolodated into one item that can be used on any heirloom of any type or any level.
This is dumb.