I'd like to see OGH:C level progress be preserved across game accounts rather than individual characters.
With OGH:C materials now being an important item for HoL item enchanting there's incentive to run Challenge Glastheim, but the grind to level 10 is incredibly slow as it nearly takes an entire month (24 runs) to go from difficulty level 0 to difficulty level 10.
It feels absurd to need to do this for every character you may want to run OGH:C with, let alone run the instance enough times to get sufficient temporal gemstones for a single HoL accessory enchant (20 runs on average at level 10 to get 90 gemstones).
I would like to have the method of crafting Grace of Life as an alternative to dungeon farming as since grace farming is limited to being per-character, under best circumstances most people won't get more than 5 graces per day which would require 6 entire days of repeated farming for a single opportunity at rolling a HoL accessory enchant.
Having the challenge progress be shared across characters would at least ease the burden.