#3 is a world I've been kicking around for about three years now. It might be roughly described as being a Naruto-esque world, minus the eye-hax and tailed beasts. This one has the huge advantage that I've already got a lot of the world-building done, and I can do 10k-20k on that alone. The problem is that I've never developed a plot or story for this world.
I am toying with the notion of mixing #2 and #3, with the main character being a new concept for the world -- different enough he'd still be finding everything out for himself, but having the built-in struggle against the status quo.
If you need help by way of a plot brainstorming session, I could be of service. I certainly could use some myself! Sometimes in explaining things, you fill in the gaps on the spot, and end up coming up with solutions you'd been trying to figure out for years.