thats not an option with my group. furthermore none of the other healers seem to be having a problem
All damage, bar the 'shoot' auto attack ability can be avoided. Your platform is likely suffering because people don't know how to move out of Dread Spray. I don't understand what you mean by "That's not an option with my group", of course you can run behind the pillar and LoS the damage, if you're not, then you're going to have to pop a healing cooldown and have everyone use a defensive to get through the damage.
You really should have people avoid the Dread Spray, there is a pattern to each platform, that can be easily learned, which will minimize the damage everyone takes significantly. Without a WoL parse I can't give you any specific advise as I don't know how you're healing.
Keep a healing rain down centered on the tank (if you need to) and people can run in and out of that as they are collecting the globes. Healing Stream totem also does a lot of passive healing. Riptide + healing wave but if you are really struggling just pop spiritwalkers grace as you run around avoiding multiple ticks of spray so you don't get feared and chain heal the group up.
The platforms on 25 man have always seemed fairly simple to me to the point of being undertuned. I would recommend using Spiritwalker's Grace (possibly glyphed for a longer duration) to make it easier for you to pick up the orbs. As the healer, you want to be picking up any orbs near you in favor of DPS having to run to them, because the more the DPS has to run around, the longer it is before the add is down, and the more possibility they heal the add. A Healing Rain should hit most of the raid, and you can glyph Riptide and just have it rolling on all 5 people if you are really having issues. Not running behind pillars for Death Blossom is complete idiocy. There just is no reason for it; the rest of the damage is fully healable.
Also, there is very little raid damage on this fight when you are not on the platforms. Don't be afraid to blow Healing Tide and/or Ascendance if you get in trouble, You barely need either otherwise.
My guild started progresson on Sha of Fear last night, and everyone was taking burst dmg all the time. I think it's a matter of people having to learn not to nonstop taking the orbs before they are healed up, and atleast have the healer take up some orbs aswell. Tremor is a very good totem for the fight, because you got a lot of room for error to be taken into a fear. Have people be able to heal themselfs up when either taking orb too or when hiding behind pillar.