Change timeline visualization and data
A few years back, we implemented a timeline feature  that didn't really stick.
The idea is to improve the visualization and the data shown to make it beautiful.
First, change the visualization to this https://github.com/marmelab/EventDrops to make it more attractive.
Second, add additional user events. For example, check the c_item_property table for everything created or updated by the user in courses/sessions and show it on the graph in one line per tool (General, document, work, forum).
If the skills tool is enabled, also check when a user is assigned a new skill and reflect it on the timeline. If the skill is attached to a badge, show the badge.
Improve the visualization (pass on to the designer for that)