As more promos started coming out, the possibility of Shane McMahon being the one behind them grew. Shane and Stephanie have always had significant roles in their family company.
When Vince was relieved of his duties as the boss, the tradition of passing it down to your real son did not continue. The duties were given to Vince's son-in-law, Shane's brother-in-law and Stephanie's husband, Triple H.
Shane could return because he is jealous and enraged that he was not named the new boss. Stephanie could return as well and be involved in the feud between Shane and Triple H. There is some significance to the fact that their is a boy and a girl in the promos and they could be representing the children of Vince McMahon.
Lately Shane has moved away from the WWE to do his own thing, but with the WWE Network ready to premiere and the company possibly moving away from the PG era, I'm sure he will be willing to return and draw some buzz around the wrestling world.
What We Should Expect If Shane and Stephanie Return
Majority of fans are hoping that the "end of the world" could be the "end of the PG WWE world." Since the company has gone PG they have slumped in their ratings and angered fans and former wrestlers.
Shane's return could spark the end of this PG world as he tries to gain control of the company and change the atmosphere in the process. Shane has been one of the craziest superstars and was involved in some wild matches during the "Attitude Era." If he still has it in the tank, Shane could deliver a "coast-to-coast" to Triple H that causes him to be cut open and bleeding, he could help the company start to get their edge back.