So I was thinking that players should be able to Buy/Sell each other stuff through the Trading-post. We could Buy/Sell rss packs, crafting mats, speed ups, medals & hero items by placing them on the auction house and paying a small posting fee and waiting for another player to purchase said item for crystals only. This would give the Trading-post more value than just being a way to send rss to guildies and allow the company to still make money off of this feature.
While the idea is a good one, it would never happen. IGG wants you to keep buying their packs as opposed to setting up a trade network among players.
I occasionally play Guild Wars, and they do have a 'Black Market' that players can sell weapons and armor and other items for in game coins, which is pretty cool, because it allows you to get rid of things you don't want, and save for things you do..