I have a feeling Rauner will be the Chris Christie of Illinois; a GOP governor in a liberal state that infuriates both liberals and conservatives with his pragmatism. Because of that, they see him as a threat and will do whatever they can to destroy his reputation, even before he becomes governor.
A few things:
1. Christie doesn't need anyone else's help destroying his reputation, his corruption, obnoxiousness, and general awfulness have more than done the trick.
2. Christie wasn't the victim of some sort of vast left-wing conspiracy, no matter how much you wish it were the case.
3. The idea that either the New Jersey Democratic or Republican Party establishment saw Christie as an enemy, let alone a major threat is beyond laughable. In New Jersey, the party bosses on both sides have one concern and that is "can I make money working with you." Christie was corrupt enough that the answer was a resounding "yes!" As a result, most major elements of the New Jersey Democratic establishment either stayed neutral in 2013 or actively worked to get Christie re-elected from behind the scenes (much as the New York Republican establishment did for Cuomo in 2014). There's a reason Buono was the only Democrat who ran against Christie: the Democratic bosses made sure the strong potential candidates stayed out of the race (which isn't to say this is the only reason Christie won re-election, but it helped a lot).