#2 CM Punk vs Roddy Piper
There are few wrestlers on the roster today who weren't inspired in some way by Roddy Piper. Even athletes outside the business took elements of the Hall of Famer's legendary persona. He's even the reason that Ronda Rousey refers to herself as Rowdy.
When Piper passed away CM Punk made sure to pay his respects via social media to a man that had inspired him to become a wrestler. Seeing that tribute from Punk would have likely conjured up thoughts in many fans' minds of what could have been had the two ever met in the ring.
A match between the two would have been great, but the promo battles would have been even better. Piper and Punk were two of the greatest promos in the history of the business, and it's a shame they weren't closer in age so that they could have had a program with one another.