Why was Hillary seen as the 'pro-WWC' candidate in 2008?

[Mad Deadly Worldwide Communist Gangster Computer God]

Hillary was consistently seen a the WWC-friendly candidate in the 2008 primary, whereas in 2016 she lost most of her credibility with that group to Sanders and was clobbered by them for Trump.  Putting aside the email and Benghazi scandals, she still carried the same baggage as she did this year, including ties to Wall Street, a mixed record on trade deals, questioned involvement of her in her husband's scandals, strong support for gun control, and a whole bunch of other things that normally wouldn't resonate with working-class voters.  Even though she outperformed Obama substantially in the primary with them (while holding her own with minorities), Obama managed to do much better with them in both his elections and get them to turn out for him.

So, what happened, exactly?

[twenty42]

She was a candidate for the "change" party in 2008, whereas in 2016 she was an establishment candidate for the party in power. That really makes a big difference in how you're viewed by the voters. People who are unhappy with their situations are likely to vote against more of the same, and Clinton was on opposite ends of this in her two campaigns.

[LLR]

She was white

[VPH]

Compare swing maps from 2012-2016 with county maps from the 2008 primary. Oftentimes, it looks like the coutnies that Obama did especially well in (suburban and some urban ones) swung to Dems in 2016. Hillary's strongest were often strong swings towards Trump. She was definitely perceived this way.

[Mr. Morden]

She was white

Yep.  Obama was running on a coalition of blacks + "wine track" whites, which left Clinton the "beer track" by default.  If her chief rival had been Mark Warner rather than Obama, then the coalitions would have been completely different.