#2 EC3
Out of everyone on this list, EC3 may very well have the most potential, in regards to big-time, main roster success. As a 16-year veteran of the sport, EC3 has been all over the map. In fact, this is his second go-around with the WWE. Back in 2009, EC3 spent a few years in the WWE Developmental System where he competed under several different names, most notably Derrick Bateman.
EC3 had the best run of his career with TNA Impact Wrestling. While with TNA, EC3 would make it to the top of the roster, where he would actually win the TNA World Heavyweight Championship twice. He would also win a number of other Championships, including the Impact Grand Championship.
EC3 and Paul Heyman are both very astute, high-profile gentlemen. I have a feeling that these two together could create a very interesting story. It would be a slight change of pace from the normal Paul Heyman client, but then again, when has anything ever been "normal" in the Heyman Hustle world?