Originally Posted by
Callei
Some bosses had an AoE debuff that required a specific class to clear in Molten Core; either those debuffs would need to be removed, removing the big challenge of that fight, or they'd need to be debuffable by any class with a cleanse/purge/etc. to avoid people refusing to take along, say, a priest to Challenge Mode Molten Core (random class pulled out of thin air for rhetoric's sake). Others like Geddon needed an ass of fire resist and precise positioning; this is another example of the mechanics themselves needing to be altered to retain challenge without dooming the group because they're not wearing a trinket from 30 levels ago instead of just the numbers being dialed up.