It’d be cool if the first version, which could also serve as a lighthouse, let us edit our old posts and add territories.

I don't understand your "lighthouse" metaphor.

As for editing old posts: remember that SN timestamps them after the editing timer expires. Allowing a new edit window means the site extrudes an arbitrarily willowy tree of timestamps, rather than the slightly neater graph it currencly creates. It's manageable although adds complexity that might not be preferable to simply replacing the chore of editing an old version with the opportunity to release a new edition.