You are probably right. Special elections are message sending elections. And if she keeps her teeth clean, incumbancy is always a big plus. And more folks will vote. I suspect the GOP turnout, really, really sucked (the GOP took this race for granted, which was certainly reasonable per the numbers). That won't happen as much in a regular election.
Also, the GOP in Ohio has some very serious problems (specifically a RINO problem, plus political scandals). Republicans win when they act like Republicans, not RINOs. I was worried that it would be much closer than it needs to be. But a win is still a win. And hopefully the GOP will draw the right lessons.