Certainly stronger, if for no other reason than his candidacy provided information about where the electorate is heading.
Sanders might not be boosting turnout the way he needs to for his plan to work, but he's undoubtedly the one candidate out of both parties who is exciting young people. The one constant throughout the primary, whether you look at state or national polling, is that Sanders beats Clinton by very high margins among young people. There are economic reasons for this:
https://newrepublic.com/article/130220/baby-boomers-dont-get-bernie-sanders
Unfortunately for Sanders, older people are more likely to vote than younger people. Still, given the trends in the polls, if this primary were held 4 years from now I think Sanders would have won both Iowa and Nevada if everything else were held constant.
As for the Republicans, Trump is death among young people, and the rest of candidates barely register.
Democrats need to figure out a way to convince young people that they can effectively respond to their economic insecurities. .