While there are many compelling and underrepresented settings, I think we (by "we" I mean RPG players) would be best served by George crafting his own original world. It's more work, and doesn't come with a fan-base and built-in recognition, so it's a financially riskier path. But I want to see what George can create with minimal external influences or constraints. That's the world I want to explore and experience.
Obviously, my opinion is biased.
But my respect and admiration of Mr. Ziets comes through directly working with him in domains such as these. I suppose what I'm saying is that I can speak first-hand to George's abilities to create exceptional characters, places, events, civilizations. Ideally, we'll someday get to enjoy a Ziets-original setting.