Expansion: why?

‘Fitting in with’ the TEI risks becoming a new orthodoxy: we need to promote evolutionary change.
Some parts of TEI P4 were successfully experimental (e.g. the extended pointer syntax, corpus metadata)...
... some were influentially experimental and have become FaQs (`frequently answered questions') e.g. synchronization and standoff
... others were just experimental, and have been overtaken by events (e.g. writing system declaration, feature structures, terminology...)