I believe Aspect Oriented Programming (AOP) will eventually have a huge impact on simplifying large systems development, but first it needs to gain wider understanding of it’s capabilities so people can start to take advantage of it. It’s one of those tecnhologies that has such a huge potential to simplify development through the introduction of aspects to implement cross-cutting concerns, but it still has not yet made it into the mainstream.
java.net have an introductory article illustrating how aspects can be used to simplify the development of Internationalization, which is a good example of a cross cutting concern for an application.