It's not that Ohio Democrats don't have better quality people who COULD run. The problem is that they DIDN'T run--and also that the party's leadership was all too willing to settle instead for a relative blank slate in FitzGerald as its standard bearer. Cordray would have been more than a match for Kasich, but he's got that consumer affairs gig in Washington that really belonged to Elizabeth Warren. I understand it is job security, and he may have another window to run in 2018, but Ohio needed someone like him this year to go after Kasich. There was always the risk of running against an incumbent, but Kasich was vulnerable, and the payoff for taking him down would've been huge.
Also, there are several women like former Secretary of State Jennifer Brunner or even frmr. Rep. Betty Sutton who could have destroyed Kasich on his misogyny alone and easily would've won the vast majority of female voters, including many Republicans. All of that has been blown now and Kasich will march to reelection with impunity. All smug and looking better than he ever was.