Both of those guys scrambled from within conventional O schemes. McNabb even sat for a brief time, as a rookie, to learn the west coast system.
It was thought, at the time, that a scheme would need to be developed to take advantage of Vick's unique skills. Reeves went part of the way there but the called runs were limited. Vick's part in this story is that he bridged two different philosophies among offensive coaches as well as his unique skills.