Realistically Bernie is too old and too narrow of an appeal to win the primary. Barack Obama at least had the youth and could credibly claim he could bridge the left-right divide (although he didn't ultimately do it). So It's unlikely Bernie Sanders is going to be anything like Barack Obama.
That said, I do see him being something like Howard Dean, an extremely exciting candidate who appeals to the left, and maybe change the dynamics of how future campaigns are run. His best bet is too push Hillary to the left and make "socialism" not a dirty anymore, and possibly killing the SuperPAC as a credibly fundraising scheme. Those would be huge accomplishments, and would be almost as big as an impact as a Sanders presidency.
That said, I do see him being something like Howard Dean, an extremely exciting candidate who appeals to the left, and maybe change the dynamics of how future campaigns are run. His best bet is too push Hillary to the left and make "socialism" not a dirty anymore, and possibly killing the SuperPAC as a credibly fundraising scheme. Those would be huge accomplishments, and would be almost as big as an impact as a Sanders presidency.