Why don't meta sites use common tag wikis for common tags?

Question

Some tags such as discussion and retag-request have, or should have, the same wiki across MSE and all per-site metas.

I propose that tags can be whitelisted here on MSE to have their wikis copied to all per-site metas. This could be done either

1. By SE employees. e.g., Mr. Shog. or
2. Via voting; similar to that of synonyms. Would require 5 or 10 votes.