Eh, personally I see raid icons as only being useful for situations where you actually need to know where the affected player is. A prime example would be Void Reaver's Orbs; you need to see where the targeted player is so you can get away from where he's standing. Dark Barrage doesn't work this way; you don't need to move away from the person affected. I guess if you heal by clicking on people in the 3D world, it could be useful, but I've never met a healer who didn't use raid frames to target people and heal them.
Some raid frames optionally display raid icons as well if the player got assigned an icon. This visually helps healers locate which raid frame the barraged player is quickly. Of course, one can also argue that the affected player would get the "barraged" debuff and that would also show up if the raid frames are configured properly. But depending on how debuff highlighting is setup, it may be less than optimal, since it isn't a standard dispellable debuff (Magic, Poison or Curse).
And I am suggesting to make it better. Is ignorance all you have to reply with?
The code to do it isn't complicated nor tedious nor intensive. You loop through all 25 raid members, and for every member found with less than 8500 health, check for the existence of these buffs via a lookup table whose return value is the minimum amount of damage that buff can absorb and add it to their health.
And you only need to do this check in OnUpdates after you detect that Tidal Shield has gone up, but before Tidal Burst has been casted, a mere window of 5 seconds or so.