Normally, the table of contents for the next issue of Dragon goes up shortly after the beginning of the month. It is almost midmonth, and we still have only the blurb at the back of the last Dragon to give us any clues. More often then not, the "and more..." actually just means the editorial, but sometimes there are several more arcticles than advertised.
I'll admit that it is these blurbs which informed my decision to renew or not, but those blurbs could just as easily sway people in the other direction if the magazine content is interesting.
Anyone know what is actually in Dragon #428?
No clue. It's obvious that Dragon and Dungeon magazine are no longer a priority for WotC. And they are probably delaying news, or further explaining their 'going dark' decision, as it's probably crappy news for 4th edition.
The last page of Dragon 427 lists titles for 4 of the articles that are supposed to be in Dragon 428. Maybe the cover artist for that issue is late? That is the only thing they need besides the article titles/summaries to put up the page for the next issue.
Its possible the cover art piece is late
Well, now it's officialy late. And the shutdown is not an excuse anymore. 
The shutdown never was the excuse unless Wizards hired a government artist to do the cover.
Now Dragon 428 is up! Two more to go before the corporate shutdown of the magazines.