I do not know if this is the right category for this, so by all means correct me if I’m wrong.
Earlier this year I posted a similar post. I was told that maybe they needed more heroic dragons than three to create the fourth heroic collection. I was also told that maybe they forgot.
It has now been another two heroics later, High Arcane and High Scorchwing, and they still haven’t released it. The Raven Dragon has also now been released as an obtainable heroic dragon, putting them at six heroic dragons that could possible make the fourth heroic collection. (High Ethereal, High Virago, High Reborn, High Arcane, High Scorchwing, and a possible Raven Dragon)
If they did forget, then forget everything I said and I hope they do add it.