Many projects over time have been acclaimed "ETH killer" including EOS, but with time the hype dies down and all attention goes back to ETH as usual. I think what ETH needs to improve on truly is fees and speed of transaction which also points to scalability improvement. But however, this doesn't mean newer projects are better off, they need to experience the kind of traffic ETH network experiences before we can term them as "ETH killer". ETH in the real sense is far better than most of them.