Ohio has 2 entrenched incumbent Senators that both parties can't knock off
Brown is not entrenched. 2006 was a MASSIVE Democratic wave, and in 2012 he got roughly the same margin as Obama. If Kasich runs in 2018, he'd win by double digits. Tiberi can beat him in a neutral year. Even Mandel is not as bad as the red avatars make him seem.
Ohio is going the way of Kentucky and WV. It's only a matter of time. Florida, however, looks promising in the long run, so I think they are making a mistake backing off on Rubio.
The Ohio GOP may be one of the most competent state parties in the country, but nothing suggests the state is going in the direction of Kentucky and West Virginia, which isn't a very apt comparison because Ohio has always has been swingy and doesn't have much of a Conservadem tradition like those states do. Ohio also has more urban territory, though I'm not sure if the fastest growing areas of the state are Republican or Democrat-leaning.