#3 Bobby Roode
The Glorious One has worked as a face on the main roster to the shock of many. The mega 'over' theme song gives that a super boost of course, but either way, it has worked. Roode is a much better heel, however as he can turn the crowd on him in the blink of an eye.
He can give the mid-card of SmackDown an injection of life. Imagine if at WrestleMania we get a face Rusev versus a heel Roode.
The crowd would be on fire for Rusev because that is how good Roode is as a bad guy. Once, he is done in the mid-card he can easily fit into a top heel role. WWE shouldn't waste any time building him up as a heel.