#4 - I have to agree with #4. The problem is not that the democratic party stole the nomination, the problem is that the current democratic party platform doesn't necessarily represent all of the interests of todays liberals. Bernie's platform addressed a number of subjects that were not at the for front of the democratic party platform. It appears that the DNC is being forced to address some of these issues or loose votes.
Unfortunately at this time there really aren't any viable third party options.