First off I would want to get a good handle of what the technolgy is capable of, and what it's limitations are.
Secondly I would start collecting as much data as I can relevent to the project.
The game I would design would be a Story which is told through a chain of existential type puzzle's and cunundrums, questioning and trying to solve things like moral, and ethical problems along the way, However more along the line of star trek style ethics, It would be a open world game but you would be directed along the way, not quite as open world as GTA though.
Basically the only way to win the game is by being a nice, cooperative person, you can solve as many puzzles as you like but ultimatly until you have been 90% cooperative to every one you won't win the game, there would be many tricks along the way to try to provoke a negative response.
But the story would be solid, and it would have things based on a psycholgical study of emotional response patterns to garner which games and puzzles worked the best, I mean you test everything doubly so, when your covering virgin ground to see if it works.
The way I see it, this technology can help many people learn how to think more clearly and positively about the real world they live in, devloping real world problem solving skills.
I would want to take advantage of that in any VR game I built, But it seems to me seeing as we are dealing with a perfect example of first person perspective, dialouge, thinking based games that draw you into it is what I think would proberbly be most effective.
I mean if we can just sit there and be entertained by a good film where we don't interact with it at all, (I Still love a good film!) It wouldn't take too much to write compelling games in a whole new way with this new form of media.
Maybe call it: Walk A Mile In My Shoes