I've gone ahead and marked .ucfirst and .lcfirst as deprecated in Rakudo.
...however...
In reality it's the spectest (roast) suite that officially controls what
is in Perl 6 (not the synopses), and there are still a _lot_ of instances
of lcfirst and ucfirst hanging around there.
So as long as the spectest suite expects ucfirst and lcfirst to work, I
consider them to be a required part of Perl 6 and this "bug" report is a
bit premature. :-) :-)
Pm