Which is exactly why one of those every other candidates will get elected. Bernie Sanders and Rand Paul will both be characterized as fringe crackpots who are almost certifiably insane. The people who actually vote and wield money/influence will never back them.
I have very little doubt that Hillary will win the nomination. I also think she will win the election. The Republican candidate pool is a clown car of past failures. Santorum, Perry, Huckabee, and some guy with the last name of Bush who can't deny that his brother was a complete disaster as president.
Hillary's misdeeds, which the Republicans harp on so much, are Benghazi, Whitewater, a private e-mail server, and some other potentially shady stuff. Fox News, Drudge, and WND make a big deal about all of this. Most people don't care. At all. Republicans like to pretend that the Clinton is name is tarnished, but I'm pretty sure at least 50.1% of people still long for the days of Bill Clinton in the White House (compared to any one other person, at least).
My prediction: Not many people will be able to name a Dem candidate other than Hillary. A lot of people will be able to name at least a few of the Republican candidates. Hillary can begin her presidential campaign much earlier than any of the Republicans who will bicker and throw each other under the bus. I give her the best chance of winning at this point.