logging.basicConfig is only run ONCE for the python session. It's an application-level initialization of the logging module, so it shouldn't be run more than once. After that, you'll need to change the log-level via the loggers:
logger.setLevel(logging.DEBUG)
or via the streams attached to those loggers:
for handler in logger.handlers:
handler.setLevel(logging.DEBUG)
pymel 0.9 uses and initializes the logging module, and allows user-customization throught the pymel.conf file.
Also check out the Logging-Menu, which allow the logging module to be administered through the UI:
import pymel.tools.loggingControl as loggingControl
loggingControl.initMenu()