The way we play, unused cards, which could still be played, are not discarded into the dead pile, but to the discard pile instead. Unused or duplicate specials/universe cards go to the discard pile. Once those cards are used, or if the specials belong to a KOed hero and are therefore unusable, they go into the dead pile.
I prefer this rule because I think it gives both players a fair chance to use all the specials in their deck. It makes future hands more exciting because you saw which specials your opponent discarded, and you know they are back into play when he reaches the end of his power pack.
i think this is a great idea, you still get the disadvantage of dupes, but later in the game if it ends up going to the power pack you get a few extra cards at your disposal.
it would open the deck building process much more and flexibility