formulaic; showing no original thought or creativity

Word Origin for paint-by-numbers

C20: from children's painting books in which the colours to be used are identified by numbers on the design to be painted
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Examples from the Web for paint-by-numbers

  • Many Republican wags, such as David Frum and Erick Erickson, are already onto the Boehner paint-by-numbers game of the “Pledge.”

    Paul Ryan Breaks Rank|John Batchelor|September 26, 2010|DAILY BEAST