Just my personal two cents, something along the lines of Quest for Glory would be sweet. I've always thought QG was a perfect mix of adventure and roleplaying. Sure, I'd get stuck OFTEN in those games, but at least I can go out and work on my character stats and loot a bit while trying think out puzzles. And heck, they just had awesome character development and stories.
All too often these days 'RPGs' are more RPG than they are adventure. I think doing it the QG style (more adventure and then RPG) would be awesome. I have yet to see that replicated (even in the Elder Scrolls seires) properly.
It's always been my opinion if someone did something QG style, that would still be marketable to mass audiences: an adventure disguised as an RPG. You'll actually trick people into playing a good game instead of firing a gun at the same 10 enemies for 48 hours. :-P
Definitely worth considering, POStudios!