The standing issue is going to be a little challenging for Count I (1st amendment). The EFF's argument is basically that these organizations' expression has been chilled by the general knowledge that their communications are being collected. Laird v. Tatum seems like challenging precedent to overcome: http://en.wikipedia.org/wiki/Laird_v._Tatum (Court held that the fear that the army might cause some harm in the future with information collected pursuant to surveillance was an insufficiently concrete injury to support standing).
The Due Process claim is iffy because it does not seem that any plaintiff has actually been prosecuted pursuant to a vague legal interpretation. If some poor sap got prosecuted in a case involving that legal interpretation, that would be a much better basis for a lawsuit.
I hope they make some progress with this, but I'm not optimistic because of the standing issues.
As an aside:
I personally don't think litigation is the best way to approach privacy issues. I strongly recommend watching this documentary on Prohibition: http://movies.netflix.com/WiMovie/Ken_Burns_Prohibition/7019.... Carefully pay attention to the section describing the Anti-Saloon league, and specifically this guy: http://en.wikipedia.org/wiki/Wayne_Wheeler.
When you think about it, the 18th amendment is a marvel. Prior to the 18th amendment, the federal government derived 30-40% of its revenues from liquor taxes. The beer barons had paid off plenty of political types. The nation was full of Irish and German immigrants who loved to drink. Yet, in 1919, the Anti-Saloon league and associated lobbyists got the 18th amendment passed to ban liquor. It was an incredible political maneuver.
They didn't accomplish this via litigation. They accomplished it via single-minded politics: Wayne Wheeler would lend the League's support to anyone who was in favor of Prohibition, regardless of their stances on other issues. He drew on the Protestant community, anti-Catholic sentiment, and the womens' vote (the suffrage movement in the U.S. was heavily driven by the desire of womens' groups to ban alcohol). They had a singular, clear, if ambitious, end-goal: the banning of alcohol.
If people are interested in electronic privacy, I think there is a lot to be learned from the success and methods of the Anti-Saloon league.