Completely agree with you, mate. eWASM is much faster and efficient than the current EVM. Using a tried-and-tested programming language like WebAssembly could really make smart contracts on Ethereum much more reliable. The only issue with adopting a new virtual machine is the steep learning curve from existing Solidity developers into WebAssembly. Besides that, it'll be a troublesome process to migrate dApps and tokens from the EVM to eWASM. I'm sure that the ETH dev team will come up with a straightforward solution to "tackle" this issue.
But first things first. Before we talk about eWASM, ETH needs to become a full-fledged PoS cryptocurrency. After scalability issues are solved, the ETH dev team could decide to go all-in with eWASM. There have been talks about adopting ProgPoW before going to PoS and the likes. As long as ETH takes the "safest route" in terms of development and innovation, nothing should go wrong. If WebAssembly works on EOS, then I think that it'll be the same for Ethereum. Just my opinion