W.W.Welshman
Having been privledged to be on the initial Cadre for the C-17 I can confirm that this is an awesome aircraft.
Your info is almost correct as it can back up a 2% slope fully loaded (164,900 lbs) but needs an lots of throttle at that weight. The Assault landing is a landing with full flap, 5 degree glideslope and max braking effort.
What you are talking about with 25,000 Fpm rate of descent is the "Tac Descent". This is completed with full Speed Brake and reverse idle whilst pushing the nose down. 25,000 Fpm is a little over the top but 16-20,000 is normal. Completed one with a USAF crew whilst carrying an M1-A1 main battle tank, great fun but made me pray i'd restrained it correctly.