With 7.6 Teiid Designer will be managing a new Model Extension framework which allows users to define Model Extension Definitions (MEDs) to inject additional properties into relational, web services, XML document and function models.
Initial design is to maintain a registry or both built-in and user-defined MED's within the user's workspace/.metadata/org.teiid.designer.extension folder.
Designer is also maintaining a similar Teiid Server registry in workspace/.metadata/org.teiid.designer.dqp
The "Import VDB" feature will probably need a place to store a registry of "Translator Overrides" so user can re-use these across VDB's rather than re-inputing these properties manually each time in their VDB editors.
The Data Tools Connection profile registry is also stored in a workspace/.metadata/org.eclipse.datatools.connectivity folder. Data Tool provides input/export features for persisting portions or all of the profile registry across workspace, but requires user to import/export each time.
Eclipse's ".metadata" folder concept is good from a single workspace standpoint, but these registries are:
1) at risk of being deleted if workspace is cleared
2) registry data (i.e. files) are not available/exposed for proper version control
So a solution might be to create the concept of a Global Workspace Location. This location would be set by the user if they choose. This location would contain folders for Teiid Server, Model Extension, Translator Overrides, Connection Profiles such that if a user changes workspaces they wouldn't necessarily have to re-import all of this data.
Maybe provide a "Global Workspace Explorer" view that would have some features/actions to do some appropriate management of the artifacts.
This would be a Usability