Storing lang pack meta as strings in langconfig.php has an advantage of history tracking and branching. See for example MDL-17349 on how to use it for storing the up-to-date record of who is maintaining the lang pack and who all was ever maintaining the pack in the history.
From the pragmatic system design point of view, these information are properties of the language pack entity and should become columns in some AMOS table. But I incline to keep the current way. Objections?