@proxiss: I hoped to temper the article with an understanding that it’s practical in more complex applications and, in my experience, has actually led to less code and greater simplification because of it. With some of the upcoming stuff I’ve been working on at Squarespace, for example, this pattern has come to good use as different models have to represented in different states, including config dialogs, in-document layout, etc. Adding new models to edit is a matter of editing one component, not three. I’ve had other projects, as well, that have come close but would have been easier to develop using a stricter MVC methodology. Instead, there was too much dependence between components, making it harder to work on as the application got more complex.
@Charlie Clark: The section on Progressive Enhancement was meant to address the issue but admittedly, didn’t specifically mention server-side validation. Yes, it’s always important to perform these tasks on the server-side. “Never trust anything from the client.”