IMO the twist would be to select one person.
Everyone expects a council, and a council just doesn't fit the Horde.
It doesn't need to 'fit' when the position of Warchief and a sole leader has been shown repeatedly to lead to tragedy. Even Thrall was shown repeatedly to have poor judgement in regards to many matters, including putting Garrosh in a position of power in the first place. A council would be ideal as it would allow every race within the Horde to stand on relatively equal footing (which also ties into the whole 'the Horde is a family' thing that's been going on lately) whilst allowing for more diplomacy.