Frankly, since there is van and shuttle service from Fraser to almost anywhere in the winter Park resort area, anyone that wishes to use the CZ to get to Winter Park resort can already do so with a little substantial additional time spent.
Corrected that for you.
The reason for the CZ stopping at Fraser was the lack of a suitable platform at Winter Park. This has since been corrected, with a 950 ft. platform, which is certainly long enough going eastbound, and probably long enough going westbound. The majority of the Fraser traffic is going to Winter Park, and the small minority going to Fraser can, yes, take the shuttle bus. It would now make more sense to stop at Winter Park.
What's currently preventing this change? If the platform is still considered too short, the platform could be extended another carlength to the west without much difficulty. Fraser doesn't handle checked baggage, so there's no difference in the dwell time or staff requirement between Fraser and Winter Park. Surely Amtrak would prefer to have only one station rather than two. What's the problem?
There are certainly no ticketing-related issues; with the Ski Train in operation the majority of skiers from Denver will take the Ski Train, which is running on a similar schedule. The schedule is in fact sufficiently similar that if necessary local travel from Denver to Winter Park could be prohibited on Ski Train days without ill effect. The CZ would be used by skiers coming from further afield (Salt Lake, Chicago), which is already what the Fraser stop is heavily used for.