Good idea, one day I hope we get the direct STEEM <-> USD conversion but until then a STEEM DEX would be awesome. I would be happy to move my business to it from Bittrex if the platform operates as well as steemit.com does. We could also have a bunch of new trading pairs opened up against SBD maybe?
ETH/SBD, BTC/SBD ... would be neat, especially if we got SBD under control a little better.