Alexandrite into cat's eye would be nice to have, but also impossible to do in a way that doesn't make it redundant? You can't hold 303 stacks in your main inventory, can't trade more than 891 in one trade, so in order to make a cat's eye you'd need a storage NPC that would let you bank up to 30,000 alexandrite for processing, at which point... why not just make it so that NPC's stock is fed directly to Paparoon to pay off a mythic? Why not just make that part of what Paparoon does?

They'd have to add a whole new coffer for alexandrite instead, that always generates 99, and let you trade 99 for that. Which... yes, please? High-purity bayld and heavy metal plates too, maybe?