The problem with commissioning editors is, they are unable to separate the individual from the format in which they are first famous.
Davina McCall fronts Big Brother. So what, Tony Benn could front Big Brother - it's just links between the ads. and the action, which is why people tune in. So someone gets the bright idea that becuase she can interview the BB 'stars', Davina would be a hit on a chat show with real live adults with brains! Result? Flop!
Sharron Osbourne is a judge on The X Factor. In a similar format, so was Pete Waterman, and Neil Fox - they're the ones who aren't Simon Cowell to add a bit of balance. So some bright spark thinks Sharron can do a chat show with real live adults with brains....
Do you see a pattern developing here?