Well, you can write very obfuscated code if you're lazy in a bad way. Badly written Perl code is a maintainers nightmare. Perl was not designed for OO, that is, it is not pure OO-language and thus lacks some of stuff pure OO languages have.

Also, Perl's performance in some cases does not meet, for example, C performance in heavy calculations, like encrypting/decrypting (although this can be avoided by using perlxs and writing the performance sensitive parts in another language, C being the model example).