/var/log/jobsub/error.log is still fairly unusable for operations. It is really a developers log, with verbosity set to max. It should honor a verbosity level or debug level setting in a config file.
Talking to operations people, they are mostly interested in
1) user a did jobsub_client command b from machine c at time d
2) result of 1) -> success or failure, minimal response from success and verbose from failure.
The error log should probably just have the above at minimum verbosity level, and its current spew state at max verbosity.