We just opened the 3.x branch with some very useful functionality to add property widgets through the field UI to any property.
We also have a handful of features in our radar for 3.x, including:
- Property formatters
- Configurable behaviors
- Better permission management
- Entity revisions
- And full multilingual support
- Export as code functionality
- Solid Feature support
If you have any ideas or suggestions on what ECK should do, please let us know. We want to implement better cycle management for the 3.x branch, so any new features that we don't decide upon right now, will have to wait until 4.x.