I suggest making more items with diffrent rarities on diffrent levels tradeable drops & not bound in game to bring back more players.
for example Everyone farms for Radiants, but they never drop tradeable, so nobody has anything to actually reach out to another player to sell or buy unless they spend cash to open boxes and get something thats worth trading, I amongst alot of other new players that dont know values dont spend money on boxes like this, aswell as cant afford it.