I'd opt in that an Arduin game could be either a game set in Dave's 'World of Arduin' or a game run with an Arduinian feel (ie rules and general feel).
One of the biggest differences from OD&D/AD&D etc. is that even powerful characters are still less powerful than elder NPC's, etc. There's a point I make to players, that as GM I can ALWAYS beat them up, so don't rock the boat. What I mean is that there's always a consequence to actions, and a lot of powerful beings that the players really don't want to tangle with directly. I believe a good game world should have as much complexity as the real world.
The fun part of a game system is the role play and challenges of survival. The GM is hopefully keeping the game interesting and making sure the players have a chance to survive, but if they really want to kill themselves.....there's always a way <G>.
Dave rewarded smart game play and thumped stupid mistakes, at times mercilessly (at least it felt that way). How was I to know that cutting down one of the beggar mob outside Talismode would have legal ramifications? Arrested for using force on a bunch of beggars who were mugging me? Preposterous!
Make sure your players get that edgy feeling that things are not what they expect, and that danger lurks in strange corners. That's an Arduin feeling. Make politics a real feeling. Have reports of distant battles and disasters, royal marriages and deaths. Does it mean something or is it just background color?
You can do that with a small batch or races and a limited power structure as well as an unlimited game. Just make sure you plan out some of the cogs in the machinery behind the scene, the rest starts to take care of itself. Dave was always looking like he was in control, even if he might have been flying off the cuff. He had enough cogs worked out that he could drop in another chunk of material and figure out how it would work, and while we might suspect.....we always wondered what was pre-planned or ad-libbed.
So go with the feeling of Arduin, use the physical setting if you want to, just remember to keep the players wondering <G>.