FamilySearch.org Person ID numbering update
In addition to the vowels and zero, I think the letters B, S, and Z should also stop being used going forward. B could look too similar to the number 8. S could look too similar to the number 5. Z could look too similar to the number 2. These similarities could cause human transcription errors.
The hyphen can nicely break up a long string of characters, but if only numeric numbers are involved, a computer system might mistake the hyphen for a numeric minus sign. Presumably, the Person ID of 1234-567 is a valid possibility if we want to maximize the number of possible combinations, although I might reserve that specific ID as part of a set of numbers that cannot be assigned automatically. I am not going to suggest a symbol such as the greater-than sign or a period, but rather bring up the question of whether hyphen usage might cause query issues eventually.
Assuming the letters B, S, and Z are removed, there will be fewer possible assignable combinations, and even without the change, the available numbers may run out in the future. Expanding the length of the Person ID before that scenario becomes an issue might be a good idea, and the numbers could be also made semi-sortable by encoding information such as sex at birth and geographic region of birth as part of the ID number, if provided. At some point, I wonder if children will be born in space or on the planet Mars. Zeros could in theory be used to pad existing ID numbers so as to be seen as compatible with the newer ID version.