What's mystified me the most is that, as Tony says, whether total precipitation goes up or down, Canyons and PCMR have the least reliable conditions in the area, and presumably less reliable conditions than most of VR's Colorado inventory (I'm pretty ignorant about VR's other resorts though).
At the risk of getting sidetracked into the political realm, I'll briefly summarize my views here.
1) We have already had something like a 1 degree temperature increase since the 1970's. My data from 106 ski locations in North America shows no impact upon snowfall from that except at the Whistler base. There are a lot of places in that list that already get a fair share of winter rain. So:
2) We need a significant further increase in temperatures (which has not occurred for the last 15 years) to tip the rain/snow balance even at the coastal areas. For even mediocre Rockies locations like Park City, it's going to take a worst case scenario and several decades to move the needle on rain vs. snow. Coastal Florida night be under water before we see much winter rain in Colorado.
I'm guessing smart people at VR have figured this out, and since they are running a public company they are lot more interested in what they can do in the next 10-20 years, than in some speculative disaster that might cause trouble in 50 years. Canyons/Park City are a perfect fit for Vail Resorts in terms of terrain and resort ambience for the clientele with whom they have been successful in Colorado. Probably even a better fit than Heavenly and Northstar at Tahoe. If Vail ends up with a seamless 7,800 acre intermediate-oriented mountain in Utah with a nice resort town at its base, they will be delighted whether One Wasatch happens or not.
I would rate Vail's resorts overall for snow in western resort context as follows:
Excellent: Vail, Kirkwood
Very Good: Beaver Creek
Average: Breck, Heavenly, Park City if they get it (Jupiter and the upper 1/4 of Breck rate better than average)
Below average: Keystone, Northstar, Canyons (9990 is probably at least average)
Keystone and Northstar have a lot of mellow terrain where snowmaking can be most effectively deployed.