Troop Idea - Master Wizard
I'd propose this troop as a dark troop. With the ability to conjure troops similar to the witch but it actually conjures troops that you have available to create from lvl1 barbarians right through to lvl4/5 pekkas. The Master Wizard would have the freeze spell as its attack, this should give clanners the tools to attack but enough of a challenge to try and master the Master Wizard.
Having a Master Wizard would entice clanners to max out all troops in the event that they would be called forward.