When you mention decentralized exchange using atomic swaps..the first thing that comes to my mind is BartexDEX by Komodo ($KMD) team.
With so many coins already listed on BarterDEX, I don't see any close competition for 2018 (atleast).
Oh, and they have bagged the ETH/ERC20 <=> DOGE bounty claim too.
I looked at kmd last year but haven’t kept up. Can you recommend some you tube videos? How much volume do they have?
As there are multiple centralized exchanges, there will probably be a number of decentralized exchanges, competing for users. BartexDEX is an exchange we plan to cover in the future.