I think crystaloids are a very important item.I dont believe that they can be obtained only from dungeons.So i suggest that:

1)all types of crystaloids should be sold in crypt shop or the amethyst shop
2)the crystaloids in mystery shop should be sold in a better price.Not 20 balens for 1 lvl 4 crystaloid!!!

That's what I have to suggest.If someone has better idea,don't hesitate to reply!!!