It's quite hard to predict that, development might be slow, but the primary technical limitation on ETH is the low tx/s. It's hard to fix that. Even if Ethereum has more features than EOS does by next year, there is a hardcap on how much Ethereum can handle, and since it's easier to copy features than to innovate, EOS can easily copy ETH and add a few extra things in and have a much better technical basis. So while it seems possible that in the short run that ETH will exceed EOS, EOS just has a superior technical base.

Furthermore, the CTO of EOS also took part in the development of STEEM and Bitshares, so you can be very sure that Vitalik Butterin's genius is at least matched.