A Planescape Torment 2 would be, frankly, quite stupid - unless there is a way for it to totally make sense, which I doubt there is. Not to mention any licensing problems. Also any "The Somethingsomething", an adaption of something else, would be a waste of potential, I think. What would be cool would be a game as intriguing, as original and immersive as Planescape Torment, if not more so (since it shouldn't necessarily be just a copy of its design ideas and can make a strong impression all its own). You know best how to do something like this or in what franchise or even subgenre to do it.