Oh, see, video games are a whole other nightmare entirely. Not only do you need to figure out what the core mechanics are for essential conflict resolution, you have to figure out the affordances and interface between the player's intent and the machine's recognition and understanding of that intent ...

And that's why serious video game designers get the big bucks and still starve. (That and living in LA or Austin, the poor bastards.)

If you want to start thinking about interfaces that work well for video game design, tabletop role-playing games are the absolute worst place to start looking. Tabletop wargame designs (yes, even for video game RPGs) are a much more self-aware set of systems for deciding how to interface intent with mechanical interaction.

Don't get near D&D for that kind of thing. We've had thirty years of systems evolution across the board since D&D was relevant in a mechanical sense.

From a design perspective, the best way to start refining ideas is to write down what you imagine your experience to be like for the players. Screenplay format, prose, a series of storyboards, whatever, just as long as you can start imagining what the player will do and experience during play. Until you have that, you're not really building to anything.