What has Kasich done that is so unpopular?
The anti-union/anti-public employee/anti-gay marriage bill while simultaneously calling for tax cuts, a horrible budget, calling a police officer an "idiot" in a speech for giving him a ticket, having a really divisive governing style, getting a Republican kicked off a state senate committee so that the anti-public employee bill would pass, calling for large cuts in the state sales tax and income tax (although he hasn't been as vocal about this recently), plus a lack of any real improvement in Ohio's economy due to anything Kasich has done. On top of all of that, he was never very popular to begin with.