The Scheduled System Task library is a great example of an Apex Designer library. It packages a set of easy to use features that address real-world challenges and makes it easy to add them to any application.
Building a platform like Apex Designer is like climbing a mountain - progress with each step seems impossibly small, but occasionally you pause and look back to see you have come a surprisingly long way. Consider this post a retrospective of the highlights of the past ~12 months.
Apex proposed an "Instance Migration" approach. This uses a tool that reads process instance data from a legacy environment and re-creates the legacy process instance in a new target environment without the need for any direct database migration.
The Apex team worked with the customer team to create a Process Instance migration tool that reads Process Instance data from a legacy environment and re-creates the legacy Process Instance in a new target environment.