Since this site is 'worldwide' the date info should have a 3 letter month format ie:
Jan, Feb, etc. Because 1-2-19xx is confusing and read as: 01Feb19xx or Jan-02-19xx
Depending the convention you are use to.
Since the various reports that can be produced from the database and the number of characters allotted to a 'record' causes data to be 'lost' then I believe the largest geographical/political designation should come first and no 'spaces' be inserted, use of a comma or a period can suffice. Then when data is truncated only the least important is 'lost'.
@date & location display
Info for 'birth' shown as
"St John The Evangelist RC Church, Hillsdale, Bergen County, New Jersey, USA"
Is better presented as:
"NJ,Bergen,Hillsdale,St.John,RC Ch." (less than half as long, no detail lost).
Note: for the USA, the 2 character state abbreviation is probably ok and understood worldwide (same for Canada).
I'm not sure what defects your talking about, perhaps you could be clearer about the problem. What is wrong and how would you fix it or are you just talking about manual entry standardization by using abbreviation. I don't understand the date concern as Geni uses a pull down for the month in a non-numeric format (so as not to confuse the month/day).
It is easier to do or complete a merge when more detail is provided than not. So I would prefer to be presented with "St John The Evangelist RC Church, Hillsdale, Bergen County, New Jersey, USA" rather than your shortened version "NJ,Bergen,Hillsdale,St.John,RC Ch." And at the moment I am sitting with more than 23000 merge issues.
The version with alphabetic month names is only ambiguous if you start trying to accomodate multiple languages.
That said, the biggest source of confusion is DD/MM/YY vs MM/DD/YY.
So far, I haven't seen any variants that can easily be mistaken for the ISO 8601 format: YYYY-MM-DD (note 4 digit year and use of dash as separator).
That's what I hope Geni will support in the future.