Use 'mystic urns' & 'mystic plants' & the like as 'rare' ingredients instead of raid loot, tomes, shroud ingredients, astral diamonds, etc. Nerf the drop rate of these items dramatically. Problem solved.
Bingo.
They added these to the game for a reason. They're btc or bta (can't remember which) and will serve as a perfectly fine bottleneck to creating shards.
They also need to think about LEVELING crafting and leave some recipes as-is to give a path to leveling.