And as Zarhym entirely correctly points out, it's not just the orcs and humans that are all that matters now, but the entire Alliance and Horde factions that have developed over the course of the franchise's life. Warcraft started with them but has expanded unto everything else.
...the pillars of the franchise are orcs and humans; it really is the Alliance and Horde by extension, and it really is those two groups beating the brains out of each other for an extended period of time. That's always gotta be what Warcraft is about...
This is also a good opportunity to place front and center the fact that the Warcraft universe is an evolving story. It's not like Lord of the Rings, where everything that is has and (likely/hopefully) ever will be in the universe is already written in stone. Gandalf isn't suddenly going to join forces with the factions of darkness beyond the great sea while Frodo becomes the next Gollum -- but Thrall? Maybe he'll defect to the Alliance some day.* No one knows; it's evolving and ever changing.
Zarhym's full statements, after the break.