Has Hillary really shifted to "the left" due to Bernie in any tangible way though?
The cultural issues she's moved on since 2008 have become more mainstream since then, gay marriage/rights, criminal justice reform, etc. Certainly not due to Bernie. And she remains steadfast on others. And you could argue some of it is opportunistic.
She's not really budged too much on health care, BIG BANKS, trade, climate change, gun control, etc. She's spent more time blasting Bernie for being unrealistic on those issues than really outlining anything specific on those.
She remains seemingly in the "hawk" wing of the Democratic Party, and Bernie hasn't exactly delivered foreign policy blows to her.
This isn't really to criticize her on these policies, Darko knows I'm not one to throw stones in the glass house of policy, but I'm not seeing the shift that everyone keeps saying has happened.
Just to illustrate rather than claim this is some kind of definitive thing. OnTheIssues had Hillary placed in 2007 (day she announced for President) vs inauguration 2009 vs 2014 vs today:




So by their standards, it was Obama who moved her left, not Bernie. (Likely, considering Iraq, health care, etc.)
For fun, Donald Trump, 2006 vs 2011 vs today:



spoiler (click to show/hide)
spoiler (click to show/hide)