Perhaps a graphics option for replays, using the same collision detection but the fancy models (there would be slight clipping but otherwise it would be fine!)
It takes a long time to do so thats why, even if 40h a week, as said in the "recruting c++ devs" still it would take minimum 6 months maybe.
And yeah its alot hard.
You have NO idea what your talking about. This wouldn't work to good, as Fnugget said, collision detection. Making textures would become almost impossible.