Critiques of Perl (...continued):

Threads

Frankly, I haven't needed them enough to care about how the Thread development has matured in recent Perl releases. I'm sure the people who do care will work that out! Nonetheless, Python and Java both offer mature thread implementations.

XSLT

The Java community were early adopters of XSLT and thus Saxon, XT and Xalan are all, AFAIK, fairly complete XSLT processor implementations. The equivalent in Perl has been sorely lacking.

Maturation of the Perl XML and XSLT toolsets is progressing rapidly; they may never match Java's API consistency but you can expect them to be compensatorily powerful and flexible.