Well, I haven't checked, but my suspicion is that if we did that, a lot fewer of the cards would be viable to build decks around. Legacy allows for such a huge pool that we should be able to build decks around any of the cards in the hall of fame, excepting the ones that have only utility functions. What I mean by ones that have utility functions is that while something like Innocent Blood may be cool, it can really only clear the way for something else, not be the card that an entire build revolves around. Which gives me the idea of trying to build a deck with as many CCHoF winners as possible, but that's another thing entirely...
Obviously some cards make for stronger decks than others. Hopefully none of them are too broken...