I think Leo Sayer was, and is vastly underrated as a writer and performer.
Take a song like Moonlighting - in terms of evocation of a time and situation, it's lyrical storlyline is up there with anything Bruce Springsteen has offered.
Well, although I'm not much of a fan personally, the fact Leo Sayer cracked America with relative ease, at a time where the likes of T. Rex and Slade were struggling to do the same, is testament to his talent.