Reworking a site to improve usability is often considered a big deal. Jesse James Garrett (the guy who coined the term AJAX, and considered a top user experience expert) adds an interesting perspective:
We tend to think of usability as the foundation of the work that we do. It sets the minimum requirement for a design to be successful, so if you’re not doing usability work you won’t know what that requirement is. Philosophically, that’s where we come from.
I think a lot of people look at usability as the ultimate end goal of the design process, but we don’t see it that way either. We see it as the place that you start, but there is lot more that a design should do than just attaining usability.
Usability doesn’t really get at the psychological and emotional context of use. Usability will tell you, from an ergonomic perspective, what people can do with a product, but there is lot more to making a product successful in the marketplace and making a product feel successful in people’s minds. Often, we find that clients come to us, thinking they have a usability problem, but it turns out that their products are pretty usable. The reason that the product is falling short is it is not satisfying an emotional or psychological need.
— Jesse James Garrett on Ajax, Amazon and Web 2.0, E-consultancy.com, August 2007