Doesn't the dot handle multi-byte UTF-8 characters when the string is of the character persuasion and "use utf8" is in scope?

Update Perhaps you meant multiple codepoints used to "compose" one glyph, rather than multiple bytes to form one codepoint. The former is what \X does. Perl5 regex only does the latter; Perl6 is said to do the former too (u0, u1, and u2 levels if memory serves).