I'm new in Digikam but I find the tool very interesting. From the DAM standpoint I love the tag management (even if I have some idea to complete it).
About metadata, I've probably not understood everything. But:
1. I agree with the Andrius' suggestion to have all (selected by configuration) information in the same place, except Tags which needs a special interface to manage the tree.
2. Related to this, I think we could have a better alignment (or understanding for me ) between:
- Data displayed to the user
- Data entered by the user
- Data stored in database
- Data written (or not) into the files, on demand or automatically (I've not found the way not write anything automatically for example)
- Data read from file
From my standpoint Informations and Metadata are all the same. But it seems that Digikam maintains a difference (if I understand correctly) and I haven't found the way (yet) to make the bridge between them.