Loken in Halls of Lightning is an interesting fight. Currently, Loken is the mob with the most kills of players each day. I haven't done Loken on Heroic yet, only regular, but I've been watching some threads about him.
Loken has a bunch of abilities, but we'll only concentrate on two. First, he does a Lightning Nova with a long cast time, somewhat short radius, and lots of AoE damage. Second, he has an Aura which does more nature damage to you the farther away you are.
There are two strategies to deal with this. The first, "correct", strategy is to run away from Loken when he starts casting his Nova. The second strategy is to all cluster at Loken's feet, take the damage, and simply heal through it.
A lot of Holy paladins are complaining about Loken because we are singularly unsuited to healing the second strategy. AoE healers can cope with the second strategy in a much easier manner.
What's really interesting about the fight is that the first strategy is brittle. If everyone runs out successfully, then very little damage is taken, making it easy to heal. However, if a player is slightly slow to react, they may get caught by the edge of the Nova. And they end up taking *more* damage from Loken's Aura than if they had stayed at his feet. That can easily kill them, which makes losing the fight more likely.
The second strategy is robust. The damage taken is a fixed, known quantity. As long as you can heal through it, you're good. There's a high initial barrier, but once that barrier is met, the fight becomes a lot easier. Not to mention that it increases the time DPS stays on Loken, making the fight end faster.
Ghostcrawler is insisting that this fight is still doable by healing paladins. And he's probably right. But if there's a brute-force strategy that paladins can't use, the player base will probably push towards that. Perhaps the only real solution would be to make Nova insta-gib people, forcing people to run out.
Edit: corrected the description of Loken's Aura.