I originally used true as the default for mapReduce command's verbose option, based on the MongoDB manual documentation. In hindsight, there appears to be an error in the documentation (see: DOCS-11265). Based on the logic in mr.cpp it appears that timing info is excluded from the command result unless verbose is explicitly defined as true (i.e. the default is unset and effectively false).

This is related to PHPLIB-309, where my pedantry for specifying default values according to the server docs result in a bug for PHPLIB and mongos deployments. Let's just remove such defaults entirely and allow the server to enforce these (all the more as there isn't a mapReduce spec saying that the driver should enforce a default value).