What interview?
And hah... I remember pre-gvg there were people arguing that the card would not be played. They were idiots, but MFB is a card I knew would be great immediately since I had been playing a lot of paladin in naxx (when it was bottom 3 in terms of class power).
Most people considered MFB to be a great card before release. Yeah yeah there are always those people who say something off base, nothing new. Besides GvG was our first expansion so we didn't really have things figured out back then.
Worst card in the game that still sees play? That's a tough one. I have a bunch of cards that I think are complete trash like Savagery (which I think is significantly worse than Purify) It's probably some RNG card with a possible downside.
I think my top 10 worst cards in the game would be:
Warsong Commander
Arcane Golem
Demon Fuse
Majordormo
Poisoned Blade
Mogor's Champion
Felguard
Servant of Yogg Sauran (in terms of raw win/loss rate, this card probably counts)
Savagery
Eye for an Eye
It's not Eye for an Eye, Savagery and Felguard because not only do those cards not see any play, they are classic cards and were available with Magma Rager. This other bad card came after the classic set, most likely in GvG or after that.