Well, this is my first post in here, I found a link on K10K to meg's article. I'm just starting out in web design, but I think I have a pertinent comment.
The thing with "The element has been modified to enhance its purpose, and that is a *good thing*." is that I believe users are not pro-change. In that sense I mean that for anyone witty enough, discovering the workings of a navigation is fun and interresting. But for the average user, I don't believe he has that adventurer sense but more of a "What? why is'nt this working like it's supposed to?".
Although I do have to agree with grogg, change encourages evolution, hence amelioration.
But I also agree with Meg and M. Nielsen, too much of a change or a major change in the "way" this work is wrong, it'll leave the user in a frustrated position or a "scared" one.
So these were my though on this topic, as a young designer, I believe I am pulled toward changes or experiences, but I also think there is that other realistic side to it that matters maybe even more.