I have flown in and out of Aspen many times. The minimums are very high because of the terrain. Normally a standard ILS can proceed down to 200 feet above the runway altitude. At Aspen the minimum decent altitude is 2383 feet above the runway. That means the airfield has to be above normal VFR minimums to land. If it's not you go to Denver and the people are bussed up to Aspen. Bussing people from SJU will not be a option.
You also over look that a normal glidepath angle can be flown into the Aspen runway. That is not possible at EIS unless they change the runway orientation which has been discussed but is very expensive.
It's possible a curved approach using GPS could be constructed however I question if it can be done and meet the TERPS criteria if it has not already been done. It's not expensive since ground based equipment is not required.