No! Waves will never replace ethereum. That is my own view because ethereum is the altcoin next to bitcoin and no one cam defeat it. Though ethereum has a congested network right now, it might be changed soon as their future development comes on. I believe in ethereum because I hold it much.
I think that in this situation one doesnt need to be guided by what emotions or feelings, since the ether has a lot of perspective in the future and its not worth talking about competition with waves. First of all, for the waves to show good results, this platform will still need to defeat Stellar, EOS and other competitors.