Effects need to be moved to simpler categories, having 15-20 essential filters easily available and 'hiding' inefficient or duplicates in a 'legacy' category. We should also improve the default effects in timeline clip context menu and display only video or audio effects depending on clip type.
Effects categories are stored in an xml file, in source code: /data/kdenliveeffectscategory.rc
This file is then installed in /usr/share/kdenlive/kdenliveeffectscategory.rc
Editing this file will allow to re-categorize effects