Lester Caine wrote:
a large number of us are using genealogical databases
Sure, but that's always been outside the scope of the tz project. As the Theory file notes: the database is not designed for and does not suffice for applications requiring accurate handling of all past times everywhere, as it would take far too much effort and guesswork to record all details of pre-1970 civil timekeeping. That being said, it might be helpful to have a new file, "attic" say, that records discarded Zone data that may be useful to genealogists. If a genealogy-oriented extension to the tz database ever becomes a reality, it could take over the attic. If there's interest in this, I'll propose a new change along these lines.
and need to know that we are working with the same numbers
If you have the same version of the tz database, you'll know that; conversely, if you have differing versions of the tz database, you cannot rely on that. This has always been true, and the proposed changes don't alter this property. Stephen Colebourne wrote:
Changing something because it is "neater" or general "tidying up" are bad goals
I too was reluctant to make the change. But the motivation is not "neatness" or "tidying up": it is to avoid future political brouhahas like the ones we've had recently, brouhahas that consume far too much of our time. Avoiding these disputes requires fairness (what you're calling "tidying up"), and fairness is not an easily-omittable triviality.