#1 Jeff Hardy
Jeff Hardy's redemption arc on SmackDown was going well until WWE brought in the whole DUI angle. While it may have left a bad taste in the mouths of many fans, it has definitely opened up an interesting opportunity, one that the company should seize at Backlash.
The Charismatic Enigma is facing Sheamus this Sunday and given how the story has developed so far, WWE could surely throw in a few surprises. There's still a lack of clarity regarding whether The Celtic Warrior actually was behind the whole fiasco or whether Hardy was at fault himself.
Now irrespective of which turn the feud takes, Hardy cannot afford to lose at Backlash. If he was indeed framed and still gets overpowered by Sheamus, he'll lose most of his momentum so far. If he was at fault, losing at Backlash would start his potential heel turn with a bad result, thereby taking away from the potential of such a swerve.
Whichever narrative WWE chooses, The Charismatic Enigma needs to come out on top for it to have the desired impact.