I’ve played with all of them.
Young Legacy: She’s very good, 3 damage up front is nice, allows her to pack a punch, something that Legacy (original) lacks. However, you must keep in mind that she has less hp than Legacy (original) and that in the mid-late game, Original Legacy will likely be doing more damage, if you figure that everyone uses a damaging power, thats 3 damage right there (I’ve excluded himself, and assumed a 4 player game) plus extra damage every time someone plays a one-shot that deals damage, from double attacks (Exorcism) or from cards that deal damage over several hits (Savage Mana, Divine Focus) or from “area of effect” cards and powers that hit multiple targets (Cold Snap, Psychic Maelstorm). All things considered, America’s Finest Legacy probably does a LOT more damage with Galvanize than Young Legacy does with Atomic Glare, making me feel that Young Legacy is the weaker character. However, she’s still immensely fun to play, and caters well to people who want to play the “Superman” type and still do damage, where Original Legacy is more of a tank/support character. She is also good against villans where up front damage can be important.
Rook City Wraith: Is awful. Really, absolutely, terribly awful. She has 1 more hp than normal Wraith, but her base power takes such a hit its obscene. Stealth is awesome, and saves you way more than 1 hp if you just use it once. Sleuth is terrible. Consider: Environment Cards are usually harmful to the players. So why would you want to play more of them? This power doesnt give you much control over the environment deck, as if you see a card you like, you must either trash it (negating any advantage you might have gotten) or play it, which sets the environment up to play something else on its turn, which will likely be bad. If RC Wraith was just Discard it or put it back on top of the Environment deck I could see it being quite cool and a nice competitor for Stealth. As it is, RC Wraith is ALWAYS worse than Wraith.
Redeemer Fanatic: Likely is usually worse than regular Fanatic. But what makes her interesting is that she’s good in the situations that Fanatic struggles. For example, against Voss’ Advanced Mode, Basic Fanatic struggles a lot because of the -1 damage, she needs Absolution out to start dealing damage, and Redeemer Fanatic can get it quickly, as well as heal up in the meantime. Redeemer Fanatic plays well against Omnitron’s advanced mode as well, and is also quite good against Spite, where up front damage is not important, and it is better to focus on survival and buffing, which is perfect for Redeemer Fanatic. However, Original Fantaic still takes the cake when there is a lot of buffing going on, via party members or Plague Rat or what have you, and often shines against guys with 0 armor.
All in all, I think the original versions of each hero are stronger than the promo versions. Redeemer Fanatic probably is the best of the three as she fills in a weakness in Fanatics deck nicely. Young Legacy does the same for the Legacy deck, to a slightly lesser degree IMO. And RC Wraith… don’t play her ever.