Off the Shelf vs. Developing a New Game

The decision to develop a new game or to use a commercial off-the-shelf (COTS) game in the classroom is a really important one.
Developing a game is more expensive and time consuming than using a COTS game. However, it gives the instructor much more flexibility to include specific content and tailoring content presentation.
In the end, the decision is a pragmatic one, as you must consider whether a COTS game could provide enough depth and specificity for your pedagogic goals. Some COTS games such as Civilization provide toolkits that allow players to modify (mod) them and create custom scenarios.
If such an option is available, then a COTS game becomes a more attractive option, albeit not necessarily the best one if the overall game design does not fit the pedagogical objective.