Aye. The article is really good and choke full of ideas. Your idea about the skill challenge is definitely a great idea, and with something that size, you could probably incorporate most skills, since there is virtually no limit to what is in that maze..
For a well-balanced group, that'd be one epic skill challenge. Maybe expand on the rules as given and make it session-long, with each success or failure dictating what comes next in the maze.
My one disappointment about the article was the fact that Baphomet's stats didn't appear in it.
Agreed. We've received stats for all the other demon princes so far.