it needs a ridiculous amount of speed (190Kts) to glide (at roughly 45 degrees nose down)
'Brings to mind the space shuttle, watching the cockpit view of the approach to land is pretty startling for a fixed wing pilot. I had the opportunity to fly a modest space shuttle glide landing simulator - I could do it, but was looking out the top of the windshield for the runway.
The fact that a military or experimental aircraft can accomplish a maneuver does not mean that it's certifiable for civil applications. I believe that it's still a requirement for an airliner to be able to fly a glide approach to landing with average pilot skill. Yes, the space shuttle glides to land, but is the pilot skill "average"?
I'm not a naysayer to advancement, but the aviation industry has a huge investment in the present design standards, so we must either follow them, or devote the effort to develop new ones...