I think a kiosk where we could post trading cards and request specific ones in return would really be a good addition to the game. A card for a card, two for two, kinda like how the GTS in Pokémon works. It would make hunting certain cards down for crafting a lot easier, like the Hatching Kiosk has done for pets.
It would be nice to have an asynchronos system for Treasure Card trading and especially one in game as opposed to 3rd Party Discords and things.
I never even thought to look for a Discord. But, I've definitely wanted to see treasure card trading become more accessible for a while now. It could be just as successful and helpful as the Hatching Kiosk.
That would be a really helpful change! After actually getting into crafting I've been finding more and more need for TC but I know nothing of the average value/demand for certain cards which makes trying to trade for them seem like less of an option than farming or crafting them myself. A kiosk like that would allow people to see what others are usually looking for in return for certain cards giving a much better idea of value and much less risk of people being asked to overpay for certain cards in trades.