The difficulties of healing in melee range
Ranged classes have an advantage in nearly every situation. They can swap their focus between distant targets with ease, they can exhibit greater control over their positioning to avoid damage or gain buffs, and they're just as effective when they're in melee range as well. All conventional healers, by nature, are ranged classes, since we need to be able to heal targets that are spread across the battlefield. Holy paladins actually have the longest range of any of the healers via Beacon of Light's 60-yard range, giving us unparalleled flexibility in terms of positioning.
When we enter melee range, we give up all of that. If we're standing with the melee group, we're adding yet another target to the already dense melee cluster, which can spell doom if there are targeted AOE attacks like Chain Lightning. Our view of the battlefield is hampered by the boss blocking our sight. If there's some boss ability that forces the melee classes to run away, we are forced to stop casting while running. We're also limiting the total area that we can cover with heals by fixing our location.
PVP healers will tell you immediately that melee range is the last place you want to be, as it makes you vulnerable to incoming melee damage and interrupts. Mobs can also decide to attack you in PVE, and being in melee range means they can start pounding on your immediately. Melee range simply isn't a friendly spot to heal from.
The benefits of melee range
The number one reason for a holy paladin to enter melee range is Seal of Insight. When we strike our targets with melee attacks, our Seal of Insight has a chance to proc, healing us and returning some of our base mana. The bonus mana we see from Seal of Insight isn't insignificant, yielding 937 mana per proc. With an estimated proc rate of 15 procs per minute, we can generate almost 1,200 MP5 simply by swinging at our enemy.
The issue is that we can't heal and swing our weapon at the same time. Any time that we spend generating mana via SoI is time that we're not spending healing. The pace of healing has definitely slowed down since Wrath, but we still need to be casting something with the majority of our global cooldowns. Unless there's a specific scenario where there's no healing necessary, attacking the boss with SoI is usually a waste of time. If you're running low on mana or if there's really nobody to heal, you can score free mana, but it's definitely not going to break the bank on most encounters.
I know there are a lot of holy paladins who enjoy running into melee range in order to spam Crusader Strike, and that's fine. I personally don't like spending my mana on Crusader Strike in exchange for some weak damage and a holy power point. If you're looking to deal damage at any cost, though, Crusader Strike isn't a bad option. I used to hit Shield of Righteousness all the time in Wrath, trying to squeeze out whatever damage I could. We simply don't have any abilities that support holy paladins' doling out any serious melee damage, which explains why the shockadin strategy of spamming Exorcism is the de facto choice for dealing damage as holy.
Holy Radiance is the final reason that you'll find holy paladins in melee range. The healing from HR scales up as we get closer to our targets, so popping HR inside of the melee stack ensures that they get as much healing as possible. On encounters like Beth'tilac and Rhyolith, where there's a ton of AOE damage being dealt in phase 2, the entire raid can stack up in melee range and our Holy Radiances will generate some insane healing numbers.
Monks aren't a threat
Holy paladins might have a few melee tendencies, but we're definitely a far cry from being melee healers. While I do duck into melee range from time to time to generate a few Seal of Insight procs, it's definitely not a required technique and is often impractical. Even when we're running into melee range to spread the Holy Radiance love, we're actually playing as a ranged healing class that just happens close to the boss at that moment.
I don't see a problem with monks taking over the melee healer niche. The other healers are already running into melee range with their AOE heals when it suits them -- what's one more healer added to the pile? We're better healers when we're positioned further away, and I don't see a reason to break what's already working.
The Light and How to Swing It: Holy helps holy paladins become the powerful healers we're destined to be. Find out just how masterful mastery healing can be, gear up with the latest gear, and learn how to PVP as a holy paladin.