It Turalyon DOES bring problems later down the line, I hope that it brings back the faction conflict some how. Warcraft just doesn't feel right without the war. I feel like sarge from Red vs Blue when he has trouble trying to make peace with those dang dirty blues.
I don't think Anduin will abdicate the throne so much as Turalyon, once everyone comes back to Azeroth but Anduin, will use Anduin's absence to as justification to fully assume the role of King. He'll probably even get the public to side with him by manipulating them into believing Anduin abandoned them.