I would actually take the "blue period" example as Picaso's own styleguide. By forcing constraints on himself (like a much reduce palette), he got much more creativity out.

"When Picasso purged color from his work, he did so to emphasize the formal autonomy of the picture plane and focus on problems of form." [1]

Styleguides don't hinder creativity. They help it shine. It simply a set of constraints that help guide you through the creative process. Same as convention-over-configuration. Yes, you are forced to put certain files in a certain folders, but that just saves you time, it does nothing to stop you from being creative.

[1]http://galleristny.com/2012/10/from-brush-and-palette-to-pri...