program selection system

Executable requirements looks like a great technique, just as using tests as specification sounds like a great idea. These techniques and concepts are radically changing the way software can be specified and produced in agile teams. On the other hand, FIT has been out for a while and no big revolution in software development happened (yet?). Was FIT only “another nice tool” to support agile development ? Are we expecting better tools to start the revolution ? Or did we just miss the point of using tests for defining requirements ?