Major
Nice to have
Bugfix
Major
Enhancement
You can create new types in-app, but you generically have no way to create new instances of those types.
Improvement
Even without a specialized GUI it should be possible to create and edit new instances of arbitrary types in the system (as administrative functionality).
Test
In view Administration:Basic Administration select type Flat A and in Administration:Basic Administration:Attributes:Instances create a new row, enter values and save.
Automatic test is currently not possible, because due to duplicate type names (each for abstract supertype and concrete subtype) the type tree is not scriptable to the extent that a concrete subtype could be selected unambiguously.