It's really interesting to find that Ancestor's Call is a card that counters Patron Warrior and Secret Paladin at the same time --- It can drag Mysterious Challenger from your opponent's hand without triggering its battlecry, and can drag Warsong Commander or Grim Patron out so that it is much easier to deal with them in your turn. When facing face hunter or mech mage, you may get a 8-mana minion on board with Ancestor's Call while your opponent gets a 2-mana minion. When facing Control Warrior, it takes Justicar Trueheart or Dr. Boom or Alexstrasza out without triggering their battlecry.
So I tried to build a deck that works around Ancestor's Call. The choices of legendary minions are flexible. The main idea is to have a minion that triggers its effect in the same turn when it is summoned via Ancestor's Call, like Ragnaros the Firelord, Ysera, Al'Akir the Windlord or evenIcehowl.
Unfortunately I don't have enough legendary cards to test such a deck so it's just theorycrafting. I'd appreciate anyone that gives this deck a try and give me some feedback. Thanks!