Supporting and enhancing that active role for the audience is the prime objective of all interactive entertainment. Thus, perceptual factors, while playing the central role in expository entertainments, are reduced to a supporting role in interactive entertainments. They are a means to an end, not the end itself. It is interactivity. It's what this whole revolution is supposed to be about.
Cosmetic factors contribute to the success of the third step, speaking.
The industry rejects this notion. The conventional wisdom is that graphics, sound and animation are the defining characteristics of good product. Even then, the notion is little more than an addendum to the Prime Directive of Cosmetics. Industry wisdom holds that graphics are the end, not the means. This is the justification proffered for the mania over graphics.