Shattered Achievement
I agree, 2/5 and counting for the last 8 months.
Everybody now stands to the left of the dragon so that they avoid his attacks and the crystal imprisonment. (I believe you have to break people out of the crystals for it to count).
Perhaps nerf standing to the side? Allow some crystals to spawn where people stand? Make the achievement so you have to break any crystal that the dragon makes (not necessarily with people inside)?