Based on my experience, many BW developers use transformation and many of them implement ABAP in several places: Start Routine, End Routine, Field calculation etc. So these options are widely used and known.
During my trainings I receive questions from developers where we come to the conclusion that many people miss the opportunities and the power of the Rule Groups. I agree, this function hides behind a dropdown list and we can easily miss it. In this post I want to highlight the functionality behind the hiding Rule Groups dropdown list.