Not going the obvious route. Barb, Necro, Paladin. However I will use a Sorc as theory for first example:
Static / Enhant, Fire Mastery with Glacial Spike and if I remember Correctly HoTo's for Battle Orders / Command??? on switch with Spirit Monarch? Maybe Some Aura runewords on Main... like Beast (think Fana), what is a good shield with aura or helm, or armor.
Concept is basic, Glacial Spike to freeze all but Cold Immunes / Souls & Dolls, then Static (oh, forgot to Enchant Merc of course after Battle Orders) and again use Teleport (1 base) to evade. Yup, going to have to choose the other Aura support items...

you could have Faith bow on Main, but you may lose a Shield slot. Above is hypothetical, you wouldn't be wearing much MF gear this way either.
Oh, your merc could use Pride for the Conc Aura, however I think Reapers would be better (using Act2 Might aura merc of course) ... but up to you.
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Amazon: Bow, same Hoto switch as sorc for BO... Max Valk and Decoy, Act2 Might aura merc, Freezing Arrow and again using Aura Runeword items... simple slow / freeze monsters for merc and Valk to kill... the Decoy gives Valk more life and also great for holding off/distracting hoards. Build your merc how you want.
All theory, no substance.