I dislike using stars, because it provides too much opportunity for trolling, corruption, and bias, but...it might work in this system.
An added level, either immediately before or after Forge, might be a good idea, because we'll probably have a large amount of cards in both Crucible and Forge. And in each level, move between 1/4 and 1/3 cards up or down, allowing reentry (after proof of either card redesign or change of community opinion) back into the Crucible.
Sounds like a decent system.