Maybe it's a 4e preview and adventure seed that you have the option of running using 3e rules?
I suspect they might pass on 4e stats for the article when we have 4e in our grubby little mits.
Although I do like that, as written, it's potentially adjustable to any encounter level. PCs are 6th level? Adjust the villains to match. In 3e, there's not really any way to reasonably confront Vamps at 3rd or 4th level...but that might NOT be the case with 4e.
I guess we'll find out in June. Color me pink. I loved this article.
Slightly off-topic, does anyone get the impression that the lack of solid "teasers" since the Spined Devil stats leaked is because we weren't supposed to get that info until Saturday? Maybe we'll start getting more teasers now?