If State no longer wants Day, but wants to still be elite, then its gonna take an elite hire, meaning OSU would have to lure a coach from an elite school or pro team.
If they would go the route of hiring someone with HC experience and is a HC currently, then this would be my list (in no order)
Brian Kelly
Lincoln Riley
Dan Lanning
Kyle Whittingham
Steve Sarkisian
Mike Norvell
Josh Heupel
Sherrone Moore
Mike Vrabel
Brandon Staley