what's the issue with hashmal again? He isn't hard at all. If you can't draw an imaginary line once the pillars are cut to see where they are landing it's a player issue. if you cannot stand in your parties corner, it's a player issue. If you you keep on hitting the boss when adds are around it's a player issue. if you stand infront of the boss even though you are not the tank it's a player issue. If you cannot see the glowing hand in time it's a player issue.
Most of the damage is avoidable and can easily be healed by single healer per party. if too many ppl are dead for the sand bubbles just kill 2 and heal up. better than 2 or 3 bubles blowing up.