No, this is characterized as a "sneak peak". The main objective seems to have been to get the Mac App Store rolling. There is plenty of time (and at least one regularly scheduled press event) between now and next summer for Apple to pace the revelations.

There is a precedent for this in Leopard, where a significant UI overhaul and some other features were actually announced and demoed many months after the initial showing.

(Also: it's amusing that you skipped Vista.)