What's the probability of adding support for using .obj files (or some other standard format) for custom levels?

One of this game's strengths is its movement and exploration, so I want to create a world to explore in it. With the current setup its a bit difficult, though not impossible. It'd be much easier if I could use .obj's. I think you'd see an explosion of content as people do things such as download a .obj of a Super Mario 64 level.

I'll admit I see many hurdels with this, such as how to specify whats what material, how to enforce that everything is a solid object, etc...