These has been some great discussion here in terms of what people want to see in a game. I seem to see a lot of people very interested in the learning curve integrated into the game through the use of not standard control methods. I seem to sense the urge for a open ended control scheme that allows you to do anything! In addition to this people want a game thats true to skiing has tons of urban environment that are full of content to interact with.
These ideas are great and I think would really create a ski game that is worth playing for more than a week. Many games in the past like Tony Hawk's pro skater or Amped snow board games had a very limited game play depth and not much of a learning curve and provided continuous entertainment through increased number of features larger maps and more ridiculous tricks. Not to say these weren't fun games they just didn't add a lot of depth. I think these things I mentioned are key elements that are needed to make a game sell able to some on NS however I do believe that if you ever want to see a game like this picked up by a big developer such as EA or Activision your going to need a simpler control method as well to satisfy the million other fans who want a button masher. I really think there is room in a game by a large developer for an "easy" and "realistic" mode to co-exits. I think this is what it may come be some time down the road, not that I necessarily support this but it may be away for a developer to increase sales and continue to improve on the core fundamentals of the game.
With that said there is one thing that I haven't seen mention after reading through this thread (I haven't read everything so I may have missed it). Realism in my mind is essential. There are already to many games that provide incredible stunts, with go anywhere, do anything environments. However none of these provide any sort of realistic body movements, crashes and character to character interaction. I tend to see developers create their game engine and then move on to "improving graphics" or adding and insane amount of more terrain rather that improving how the charter interacts with the environment. However there is a very interesting solution that has been created, called Euphoria by NaturalMotion. Its an extension that can be added to a game engine to provide realistic body movements, interactions and essentially self preserving characters. This video shows some simulations about the software and how it can be used.
I think that integration of a simulation program like this would ad a layer of realism to simulate what happens when a skier falls, how hi body would interact with a rail, jump, tree ect. In my mind crashing, falling and injury are all key elements in skiing and are some of the major things that teach how to improve on the trick you are trying to attempt. With a basic environment theres nothing telling you what you did wrong, why you fell, or where you messed up. With a system like this you are able to see exactly how you body in the game moved and interacted with the environment and will be able to correct that the next time around.
You also have to realize that this is not some demo software, it has actually been released and used in a few games already and I have seen first hand (i own one of the games) how it can dramatically enhance gameplay and realism. I don't know exactly how much the licensing fees are for a system like this but if a game were to be picked up by a serious developer with some sort of capitol I think this would be achievable. I also think that the game would be pretty awesome if it did happen... Thats all..