I quite literally leapt for joy when Daelo, lead encounter designer, mentioned that they'll be turning blue in a future patch. It's a minor tweak to the encounter, but it will seriously help those moments when you have a void zone beneath a Death and Decay and you have a tank who is tanking loads of whelps and elementals which are already obscuring their vision. The hardest part of the fight isn't the movements, the hardest part is being able to see.
This does make me wonder what they'll do with future, similar things. The terrain alone makes the void zones hard to see during Sartharion, but the largest issue (I think) is Death and Decay. It's big, fluffy, and extremely red. Will they simply not be able to use red ground effects anymore? My raid doesn't do it, but there are raids out there that forbid Death Knights from using Death and Decay for the specific reason that it hides AOEs beneath it, so I have to wonder if there's a better solution to the problem than changing colors without removing the 'cool factor' of the DnD particle effect.