Should say, discard one of YOUR heroes. Otherwise, OPOPOPOPOP.
I really don't think that part is OP at all. You already have TC EE to discard heroes (see Beheaded) and plenty of other cards can do it, too. The main thing to discuss is the search.
Isaiah 40:8
No numbers good/evil multicolored enhancement - TC- Discard one evil enhancement to either place a discarded good enhancement on bottom of deck, or place a good enhancement from deck on top of draw pile without shuffling. After this card is played, discard a hero.
Now, were you intending for this card to force you to discard an Evil Enhancement from hand or play? Yours or any player's? Also, is this intended to be a search or a "look and place" ability? I'm guessing the latter based on the wording, but you may want to clear that up. And you'd want to say "search discard pile for a good enhancement" rather than referencing a "discarded GE".
Now, if we compare to other cards (I'm looking mainly at Isaiah-maiah/prophets and Abe's Kid), the searches, placing of cards on top/bottom of deck, all of that fits with other cards we have, which is good. But I'd make sure that the cost has to be paid by the player using it (like Seraph with a Live Coal) if it only benefits that player (remember that Abe's Kid recurs one for both players). I'd also recommend actually making the ability a search, shuffle, place. There's almost nothing that can stop a look right now, so I'm not a fan of it
My suggested wording (if you want to keep all of the abilities):
"Discard your evil enhancement in play to search discard pile for a good enhancement and place on bottom of deck or search deck for a good enhancement, shuffle deck, and place it on top. Discard your hero in play or set-aside."