Edge had a really good run when he moved to Smackdown and became one of the main players you can revolve the show's title program around. While he wasn't as big as Cena was, he was still a guy they built a show around for a good run.
Dibiase doesn't get the same stature in my view. The WWF tried to push him towards the level at one time, a couple times. But there was just something there that they never felt comfortable giving him even a brief heel title run. Sure, he could put over the Million Dollar belt being as good a marketable gimmick as they WWF title, but I don't buy that. He was a good character and wrestler whose role was to put others over on their way up the ladder past him.
He had a nice career and all, but if the Hall of Fame should really be special and the top of the game as far as leaving a huge mark in the industry, I"m not really sure I he fits.
But heck, Koko B. Ware got in. So sure, Dibiase could headline a HoF class.