>>> regex.match(r"(?iV1)strasse", "stra\N{LATIN SMALL LETTER SHARP S}e").span()
(0, 6)
>>> regex.match(r"(?iV1)stra\N{LATIN SMALL LETTER SHARP S}e", "STRASSE").span()
(0, 7)
In 2000, PCRE simply didn't support Unicode. Python 1.6 and 2.0 did (at least, based on some quick searching PCRE added support for Unicode in 2004).
"spotty" probably isn't the right word either, the change in 3.0 was to default to treating text as always being Unicode, the 'unicode' type in 2.x is reasonably complete (as these things go), just not the default treatment for text.
(So there at least was an advantage)