Brown is a terrifically good candidate and Renacci is a terrifically bad one, but if Democrats fail to take the Governor's race here, then Ohio's position in the national environment from 2016 (11 points to the right of the country, basically) will be confirmed. Saying that Ohio likes Democrats because of Brown is like saying the same of West Virginia because of Heitkamp.
That said, the Governor's race is still pretty high-undecided, especially for this late in Ohio; Cordray could comfortably win by 5 or so, in which case Ohio really is still a Tilts R state. But if DeWine wins -- and he's leading now -- then this is going to start turning into fool's gold for Democrats.
I don't know, what really matters is the margin by which Cordray either wins or loses by. For instance, how is DeWine winning by 1 so fundamentally different than Cordray winning by 1? In analyzing Ohio's partisan lean, there is really no difference.