As said above, the trick to Shade is to never let him drink by making sure to interrupt every Fireball and Frostbolt he attempts so he won't go low on mana. That and good dps, and you'll never get to the Polymorph part. Grounding totems do wonders for the spells that do get through. Also, if you interrupt Arcane Missiles, I think that's what causes him to move around, which can really make things messy.

I burn Heroisms during Flame Wreath, since that's one time that you know you won't have to move around. I've used Earth Elementals a couple times during the Elemental phase, but to be honest, I don't have a clue if they did any good. Fire Elementals on Illhoof though is the greatest show on earth.