"These operations would be a major feature of an attempt to take Taiwan by force" - I think this would fall under the fevered dreams of the airborne officer corps. I just don't see anyone (rational) making large scale 'opposed' landings or airdrops these days... Maybe if they convinced Taiwan to surrender in advance. What little anecdotal experience I have with airborne + mountains is on the "big island" of Hawaii.. many an injured ankle, knee, back..etc.. I'd wonder what a large scale jump into the mountains of Tibet would be like....