I think what made Edge a good face, especially when he first began in the wwe, was his darker, more mysterious side, that made the fans want to know more about him, and in essence cheer for him. Then there was his long run with the CLB, and after that he was face for a while, though I don't think he really connected as much as he wanted. Then, as almost a blessing in disguise, Edge got seriously hurt. Upon his return, he was able to be a face because he could use the sympathy of returning from a serious injury. But... I think before his injury, it was already well established that Edge was a better heal then face, and it was only a matter of time before Edge became heel. The injury allowed Edge to take a year off, refresh, and come back to his small face push before becoming a heel and being able to take off into a main event heel status, which at the time, and even now, is quite lacking in the wwe, hence the face/face main events at WM. Anyway I don't really see Edge becoming a face again, wwe could go into its old traditions where it used to keep heels as heels and faces as faces for the majority of a wrestlers career, which I think helps build credibility. The only way Edge becomes face again is if they pull a HHH and Edge gets reinjured and disappears for a year again, the nostalgia of him returning would be enough for him to turn face, at least for a few months. But Edge is far superior as a heel, he can get an excellent heat reaction from the crowd, I would say he is on par with a HHH in that regard, and that is why Edge should not turn face.