Agile software development is also best suited for large projects that have a great level of uncertainty in their plans and/or environment.

In the meanwhile I still support the idea of building a strong UI vision before the software development starts. You should not start coding before the UX guy has completed a somekind of UI vision statement. It doesn’t always mean a psd-file of the interface components, but without somekind of UI vision statement (or a prototype) you end up re-coding a lot of stuff afterwards.

And agile software development doesn’t change the fact that restructuring software code is difficult and takes time and often makes the codebase more unstable. Agile software development just accepts this fact of life more easily and tries to cope with it.

And since UI design changes often require major rethinking on code level it is reasonable atleast to try to minimize the iteration work. Therefore it is not a bad idea to still push prototyping and UI vision work before the software development team is hired.

The major statement concerning UX and agile software development is that UX design should continue being a core part of the software development phase. And I agree what you stated about that phase in your article.