I think if the US must continue to have such draconian and onerous entry requirements they should offer a fast track or simplified program for persons of note to attend a specific event in their field.
To not do so simply hinders the progress of human knowledge, or at least, it hinders the United States.
> fast track or simplified program for persons of note
There actually is a visa for Outstanding persons called O-1A: individuals with an extraordinary ability in the sciences, education, business, or athletics (http://en.wikipedia.org/wiki/O_visa).
All the fast track you need is to confer in a less-crazy space. In general, this works pretty well. You can publish in Springer journals, attend IEEE conferences and whatnot without ever entering USA.
However, it would be pretty funny to see NSA organize its conference in Europe to evade visa problems :D
Unfortunately this would violate some "fairness" or "political correctness" rule. It's like patting down some grandma/3-year-old girl at the airport, just to show we're not "prejudiced".
To not do so simply hinders the progress of human knowledge, or at least, it hinders the United States.