I know that this thread is too old for anyone but the author of the parent to read my comment....so this is for you. Having just come off a 2 year project I can say that your comments are the most insightful that I've read in years. Technically the project is only 85% done, but the PM has closed the project so that the deadline is met...all the remaining work is 'phase two'. Of the classic project triangle (Cost, Time, Quality) everything was deemed flexible except Time and Cost.
In defense of our BAs they did a pretty good job asking the users what exactly they would like the soltuion to do. The problem is that the answer the users gave was something like, "I'd like unicorns to dance around my office and sing Ode to Joy. Oh, and if they could fart rainbows that'd be fabulous!"
-Your friendly systems architect