Digging through log output text and find desired entries often is a pain. In log output SFDC has pre-defined set of markers (FATAL_ERROR, USER_DEBUG, etc.). Would be nice to have ability to distinguish them at first glance.
One option is to color code those markers (set customizable background color only for marker part)
Other option is to display list of filters found in log output and select which ones needs to be displayed (all checked = full log output text, default behaviour)