For those people arguing against the contents of the letter, don't forget that it was written in 1993!! That's 22 years ago.
While I'm no expert on the development of the F-16 series, presumably it was a lot less capable in 1993 than it is today. Therefore comparing the 1993 ANG WW assessment of a 1993 F-16 with the capabilities of todays version isn't very fair.