The whole landscape will be changed... Again... As the Ashmounts erupt, destroying villages, earthquakes, mayhem and destruction.
I'm not sure if this is in question format...but i think that the world, by the end of the trilogy, will be back to the way Kelsier, Mare and now Vin dream it to be. It is constantly repeated.
In book one, right at the begining, when Kelsier is at the Tresting plantation, you get the first hints of the conflict the the story...
Mistborn; The Final Empire, pg. 5
...He had heard whispers of times when once, long ago, the sun had not been red. Times when the sky hadn't been clogged by smoke and ash, when plants hadn't struggled to grow, and when the skaa hadn't been slaves...
Obviously, a portion of the conflict has been resolved, leaving the....list (if you will) with the state of the world left to repair. Quite frankly, i think It would be highly anitclimactic of Sanderson if he does not return the world back to the way it was. IT is brought up in the story far to many times to not seal it by the end of the trilogy--i think we can all agree to that.
So, really, the question is
how will the world be restored to its initial state?