In my opinion

[Bleedingheart]

UM died when Stack died. Robert Stack was the face of UM and nobody could replace him.

It is like replacing Bob Barker on the Price is Right nobody could replace him either Drew is doing alot better but he is no Bob as Farina was/is no Stack

[Oooga Chucka]

You are correct, but DF is just playing the hand he's dealt. He's a fine actor (check out Get Shorty and Snatch), but there's no way he is going to ever be considered the face of the show. It is not his fault - the show has been entirely restructured to look more "modern." He's just going along and doing what he can.