Are mainline aircraft fancy??
I don't see anything wrong with the CRJs or anything that is better in mainline.
Actually, as a couple I prefer the option of not having a 3rd person in the row. Same convenience as a single traveler: less people in your row, easy to get in and out if in a window.

Rest assured that flying into EGE is safe.
If conditions are so bad that it makes landing/taking off unsafe, they will simply cancel the flight. I don't think it happens very often.

And BTW, why Vail??
If you are coming all the way from Australia I would go to Aspen, stay in Aspen, ski at any of their four mountains.
Or Telluride, not only a great mountain but arguably the best ski town in the US.