DISCLAIMER: These situations do not happen extremely often in a raiding environment. This is simply a look into my thought process when it comes to this situation in a progression environment where maximizing throughput and mana conservation are important factors in defeating the boss encounter. The example I used is extremely specific and will probably never happen in a real raid encounter.
A good healer is able to quickly and correctly prioritize who they should focus their healing on and why that target is the right option. In my opinion this is one of the most important aspects of healing. Choosing the correct target(s) in your group/raid might seem like something that in the grand scheme of things doesn’t really matter (I just heal everyone lolz), but sometimes it can make the difference in defeating the boss encounter or not. Let me give you an example of a theoretical boss encounter,
You are in a mythic raid with 2 tanks, 5 healers and 13 dps. A giant raid wide damage ability just went out and everyone, except the tanks, are at about 50% HP. A dps warrior, rogue, mage and warlock just got a debuff that will kill them in 4 seconds if they are not above 80% HP. You have to pick one person to heal over the others, who do you prioritize?
To answer this question you need to ask yourself a few questions.
- What is the healing composition of the raid group? Do you have mostly shamans, druids or monks? These healing classes excel at clumped healing through (not limited to) Healing Rain, Wild Mushroom and Rushing Jade Wind. These healers are probably focusing the majority of their healing on melee/tanks who are usually in pretty close proximity to each other. Paladins and Priests are the two healing classes that rely on more single target methods of healing. This is not to take away from the single target healing abilities of other healing classes, but generally healing classes are categorized in this way. So in the situation listed above, as a disc priest, who should you probably focus your healing on? The mage or warlock because the warrior and rogue are going to be receiving healing from the shamans, druids and monks in your raid group before the others.
- What classes are in need of healing? In the question above we discovered who we should probably be focusing our healing on in this example, but out of the two ranged, how do we pick which one? Having a general knowledge of other classes in the game is extremely helpful in this scenario. Which of the two ranged classes has the highest passive damage mitigation? The answer to this question is warlock. We are not taking into account massive defensive CDs like Ice Block. Warlocks usually talent into Soul Leech which offers a significant amount of damage mitigation just through their normal DPS rotation. So odds are that a warlock would take less damage than a mage throughout a boss encounter due to this talent. So you should probably heal the mage before the warlock.
Obviously these are not the only things that need to be taken into account when it comes to healing in a progression raid environment. This is simply a small look at some of the decisions that need to be made when you are trying to be as effective as possible while raiding. I hope this gave you some insight into how I, personally, decide who I should heal before others and how taking the time to learn about other classes in the game can improve your performance as a healer. Thanks for reading! See you next time!
TLDR: Class knowledge (outside of your own) is extremely important in this game, especially when it comes to raiding (and other things probably? <(@^@)> ). Recognizing that certain healers are better at different types of healing (single target/multi target/spread/clumped/etc) can help you make an educated decision on who you should prioritize in certain situations. Having a base knowledge of class mechanics/talents/abilities can also help you choose between healing a rogue with feint over a mage with little damage mitigation outside of large defensive CDs. Not only will being able to make these decisions help you maximize your effectiveness on progression, it will help you increase your overall HPS on the people who need it more than others.