Yes, even Blizzard hinted at this. One of the creepy ghosts in Drustvar says something like:
"The balance that the Burning One kept is now lost."
The meaning is clear. Sargeras, despite his twisted ways, was fundamentally keeping the Void Lords at bay through his Burning Crusade. But since Sargeras has been defeated and his Crusade ended, who is going to stop the Void Lords now? They'll make a power move soon.
Alleria: "The whispers did not end after the Old God's death. In fact, new voices have joined the chorus."