MOTHER Detailed Strategy Guide (incl Mythic) for Healers
The biggest issue for healers on the site is the fact that there are LOS issues. While some AOE healing can transfer through the wall, you cannot single target those players to heal them.
Depending on what unit frames or healing add-ons you use, you may be able to force your frames to show you which players are LOS are which are not. For this reason, aside from the tank healers, AOE we healing is very strong.
You can move as an entire group using heavy raid cooldown and damage reduction. You have almost your entire group across the wall and stand immediately next to it. You drop your healing cooldown and damage reduction on the wall itself, so that it actually works for people on both sides of the wall and as they cross over. So things like spirit link, ankh totem, darkness, and barrier can all heal people on both sides. For the strata work you do want to have one healer remained behind, such as a Druid casting tranquility, to heal those who drop as the crossing is happening.
If you use this strat, you need to make sure you have strong stuns and AOE damage in order to deal with the adds.
You can hang out in the second room long enough for those three-minute CDs to come back up before crossing over. However you do need to make sure the raid team can handle all the mechanics, such as wind and the multiple lasers, for those three minutes.
Most groups send over a healer with the first group to cross over into each section. It’s important you leave a tank healer with the tank who generally crosses over last.