I think there is no comparison between Waves vs. Ethereum. Ethereum is a great project and using widely. I don't see any other coin taking place of Ethereum in near future
We can never be sure, it's true that ETH is rank as number 2 right now but the future is unknown.
The crypto market is still at its development stage, there are new competitors that will come and as the adoption increase, it will give good coin a
potential to grow. My strategy is to invest with solid coins and those undervalued coins.