I was thinking about this; is using a Famine with all its elemental damage, plus the conviction aura from an infinity on your mercenary to lower all enemy resistances to elements, any good in hell? I know that any single elemental damage wouldn't be as high as with a sorc powered up in one element, but the combination of several (maybe only two at once since so many enemies in hell have have 2 or more immunities) on the Famine runeword might make it worth it? What about with a berserker barb with all the extra magic damage?

Woulld be more effective on a pally with Conviction worked up. If you still want IAS put a non class Faith on an act 1 merc for fanatacism. This way you get way more damage from all the elemental dmg on the weapon.

Would Famine or a Hellrack Colossus Crosbow do more damage? You would be avoiding Iron Maiden with the Hellrack.