While I agree that his degree of HP scaling is a bit excessive right now, I don’t think it needs to be toned down very drastically. As others have pointed out, this is coming from a largely petless crowd and many people are weak or unmaxed.
Furthermore, is it such a bad thing that this encounter is putting up an actual fight? By it’s own nature, the Crystal gathers a lot of people to its fight, so it should be capable of battling a large crowd and punishing those who fail to act. It’s a moderately rare realm encounter that drops a relatively dangerous dungeon, he shouldn’t be a slouch who is completely non-threatening to maxed characters.
Perhaps this isn’t a popular opinion, but I stand by the position that the community as a whole (myself included) have become so accustomed to just about every boss going down in seconds that it’s jarring to see anything pose an actual threat to any degree. If anything, HP scaling is bringing these fights back to what they were meant to be like.