Like any narrative, it's going to be overstated in reaction to tonight, but it was probably understated going into tonight.
It's clear that there's energy on the progressive side of the party, and they have notched a few wins (Ocasio-Cortez and Kara Eastman being the two biggest) and had a few other impressive near-wins. But overall, the scorecard is still tilted well toward establishment Democrats. The numbers make it clear that the fever isn't running as high among Democrats in 2018 as it was among Republicans in 2010.