It's hard now, waves was one of the few decentralized exchange platforms but then lots of Chinese dex also started their business. This will create more competitive environment where waves will lose the battle.
There is only Blocknet worth mentioning, and even Blocknet is pain in the ass and not simple to use. Waves DEX will be simple and friendly to use and much more safe and faster than centralized exchanges. And Waves coin is not just DEX but tons of other stuff. I think there will be huge money inflow in 2018 from wealthy russians, chinese, arabians. There is a debit card in development, Tokenomica, smart contracts. Waves will be a coin that will have all the best features of big coins. So yes, expect Waves to be ETH biggest rival.