The reason the aircraft hit the seawall was not due to lack of a glideslope. It hit he seawall because it had insufficient power during the final phase of the approach and got slow. You can see this in the flightaware data and in the video> (would you intentionally flare for landing over the water?)
The reason the aircraft got slow should not be hard to nail down. This post by suninmyeyes should be worth noting:
http://www.pprune.org/7926629-post315.html
The NTSB is on it and we should have detailed answers soon.
All too similar to a RA-5C Vigilante ramp strike I witnessed in days gone by.