Currently, in order to re-use parametric components you must create these components using the following formula. This results in components that when inserted bring all sketch and parametric data along and are fully editable.
1) Create a single component, with no sub components.
* all sketches and components are at top level.
* this can be inserted with no problem.
2) For sub components:
* Create a component.
* Make it active.
* All sketches and bodies are created within this component.
* This component can be exported and re-used.
Another advantage to this workflow, the active component features are isolated in the timeline. You only see the features for the active component.