#3 Natalya
Natalya used to be a former SmackDown Women's Champion. And now, she's been portrayed as little more than Ronda Rousey's best friend on RAW. She even almost accepted Rousey's open challenge for the RAW Women's Championship. Her plans were interrupted and shot to pieces by the Riott Squad.
I genuinely think that Ronda Rousey could have the best program of her life with Natalya. If Natalya goes heel, the heat will be very real indeed.