From our experience it depends.  Most of the time the alternate is a smaller group of instruments but that doesn't mean it is easier.  It may be that with say 15 parts, each part is reasonably easy, but when it is reduced to 8 parts (and trying to make it sound close to the original orchestra) the 8 parts are individually harder than the original 15 parts.  So it is hard to say.  Each show is different (and many don't have an alternate orchestration).