#3 Samoa Joe vs. Roman Reigns would have been the ultimate WWE slug-fest
Had Samoa Joe still been a part of the WWE roster, he and Roman Reigns could have formed a Samoan faction which could have, in turn, dominated the SmackDown brand. But the actual money feud would have been one where a babyface Samoa Joe takes on the heel Universal Champion Roman Reigns for the title.
The story writes itself. Even though former WWE Superstar Samoa Joe is from the isle of Samoa, he is not a part of the Anoa'i family, meaning that he has no reason to acknowledge Reigns as the head of the table. This could escalate into a feud where the two powerhouses go back and forth and yes, Samoa Joe becomes the new WWE Universal Champion.
Even though WWE wouldn't have necessarily gone with Samoa Joe as the face of Friday Nights, it would have been a welcome change of pace. Samoa Joe connects with casual and hardcore fans alike. Unfortunately, this match never came to be thanks to his unfortunate, untimely departure.