Every application can benefit from sound engineering practices. Creating a complicated monstrosity when you're not going to need it is not sound engineering practice. At least I don't think it is, but then again I don't consider myself an "engineer."

Once again, Java is a great example. For over a decade, Java developers have piled on more and more "sound engineering practices." Maybe it's just me, but these Java applications are not easy to extend or modify in any way.