If you read what Ezio wrote carefully you will see that he addressed
both of your points: he acknowledged that a flag would solve (2) (but
disagreed that it was worth it), and he said you could use the first
expression to validate the string before using the split to obtain the
data.  Doing it all in one regex might seem more efficient, but at least
in the single use case you have presented it would lead to more
complicated code.

Simple. obvious feature requests can be opened and acted upon directly
in the tracker, but more complicated requests should be made as
proposals on the python-ideas list, and if they are well received there
then an issue can be opened (or in this case you could reopen this one)
in the tracker with a pointer to the python-ideas thread.  In most
cases, such an issue would need to include a proposed patch.

Note that we don't really have a resolution that says 'sent to
python-ideas', thus the use of the 'rejected' status.