I don't think any current coin can be the next Ethereum. There were so many things like that in the past. Couldn't compare anything to Ethereum, and failed.
Yeah, there won't be something like the next Bitcoin or Ether. I understood this truth not a long time ago. Several moths ago I believed EOS would be ETH killer, so I bought it on Ownr, later, when Dan left the project, I realized I should have invested in ETH.