Not so surprising, given Iowa demographics and the low voter turnout. Also not quite so surprising that Trump didn't do better, given that he is at least as much a personality as a candidate. I cited someone the other day who predicted Cruz would win for those very reasons.
As for Bernie's success, I looked at some demographic charts and he killed her in the 18-27 year old range, but with each higher age range Hillary did increasingly better. It's a bad sign for the Democrats if Bernie is their candidate since older people will be more likely to tolerate a seemingly moderate Republican if they can't vote for Hillary. OTOH, it's a bad sign for Republicans if Cruz is their candidate, since he based his Iowa effort almost entirely on the evangelical vote there, which isn't nearly as strong in most other states.