I'd personally want (and tbf expect if he wanted it) Vernon Kay to be offered a full time role at some point. Social Media reaction is in reality a small snapshot of overall audience, however... it's very rare a cover presenter gets an overwhelmingly positive response as Vernon does.
I think this wouldn't be a bad lineup in a few years
Overnights Owain Wynn Evans (from Salford)
Early Breakfast- OJ Borg (from Salford)
Breakfast-Sara Cox
Mid Morning- Ken Bruce for a little while longer... succeeded by Vernon Kay
Lunchtime current affairs show- Tina Daheley
Afternoons- Scott Mills
Drivetime-Zoe Ball
Jo Whiley and Trevor Nelson's show sit perfectly where they are