We've known that heroic Loken is currently the hardest mob in the game for a bit now. Alex broke the story a couple weeks ago, and Loken is currently killing approximately 1.8 times as many players as the next hardest boss, Sapphiron. That statistic is skewed a bit too, considering Sapphiron is a 10/25 man fight, and Loken is only a 5 man.
One of the chief complaints about Holy Paladins has been their relative lack of AoE heals. This becomes particularly evident when a Paladin attempts to heal Loken in the Halls of Lightning. It should be noted however, as Ghostcrawler does and I can attest to, it can be done with a Paladin healing.
It's on this note that Ghostcrawler has provided some tips on the strategy used to defeat heroic Loken. And while these appeared in discussion about Holy Paladins, they apply to any class equally well.