As it is now, either you X-Country Ski or Snowmobile to areas not accessible by any other means. The availability to those areas will increase demand by those group do not fall into that category. Snow coaches are a good idea for those that want the tour guide experience. But to take out a group of recreational users for the reasons mentioned in the video are unrealistic.
Yellowstone is for everybody. If you limit access during the winter to a select few groups, then this should apply to summer use also. Bus/Coach tours during the summer should also be the norm to have a consistent argument. Limit the number of cars and trucks. During the summer loud vehicles should also be banned along with emission testing to enter. Yellowstone is not a wilderness experience. Its nice and pretty, but certainly overused.
Sledding accidents with tour groups happen all over, not just Yellowstone. So that argument is just plain ignorant and not valid. With this type of argument that Jackie points out, we should actually close down back country access to camping and hiking because of the bear fatalities in the National Parks, or X-Country skiing because of twisted ankles.
I think that the biggest impact to Yellowstone is to have a quiet winter, (limited or no access) and then open the gates for all of the tourists in the spring. All of a sudden you have pressure on the wildlife that had not exisited all winter long.
Thats All.