A good comparison is the Canadian Liberal Party. Sure Dion and Iggy were viewed as bad 'leaders' in the eye of the public, but it's clear the party's issues stem far deeper than the public presentation, which is why even when that face became sexier and younger; people are still turning from the Liberal Party.
Actually, the more I think of it, the deeper Canadian-party-leader comparison point to Ed Miliband is the PCs' forever-woefully-awkward Joe Clark--even if he actually won in 1979. (But then again, Cameron didn't inspire the same loathing as PET did in 1979.)
