Scott Steiner as soon as he switched to singles, there was only 1 place he was going and that was the top. Kurt Angle, from the moment he debuted, showed he was potentially going to be an all time top 10 IMO & Brock's debut lay the foundation for what he was to become.
I contest Rick Rude because although he was a main eventer in WWE, he was never given the chance to reach the top of the mountain for one reason or another. Same as Hennig, both could have at the very least been transitional champs with the heat they could draw, and as someone else said no1 has ever looked better with the gold than Hennig. Rude's WCW work was very good, his lengthy reign as US champ & subsequent world title reign was probably his professional peak and i dont think anyone would have argued that he deserved them both.