This is pure speculation, but my prediction is this:
- there will be held a council to decide who is going to be the next warchief, with all the race leaders plus other personalities of matter. The race leaders are very devided in their opinions, everyone is trying to make profit for themselves.
- after some debate the council will chose Thrall as the next Warchief, but he refuses. He then speaks of what the Horde now needs and that the kind of leaders the Horde has had in the past led to devastating outcomes. He says that the Horde needs a new start. Someone who symbolises the Horde, but is a blank page other than him, who was part of the journey that eventually led the Horde to the point where it is now.
- Everyone is shattered and confused by his decision, not knowing who Thrall is speaking of. He then faces Zekhan, who stood outside. He then tells him to step inside the circle. Thrall then gives Zekhan full credit for his honor in various battles and his relationship and influence to Saurfang. Zekhan is quite terrified by this decision, knowing what burden it is to be Warchief. But Thrall says that he will be by his side as his advisor. He says that he is now home again, and will help working to build up the Horde as new. All the other leaders are approving this.
- Zekhan eventually accepts and takes the title as the new Warchief of the Horde.