review existing code and clean it up, some classes have methods that have different code to do same thing.
check the code for correctness, and fix it (example: the unicodeToMacRoman actually does unicode to latin1).
Improve performance of the translators: as an example the UTF8 translator creates a write stream, but then actually writes out bytes to your file system one byte at a time as it considers if the unicode byte needs to be made into a utf8 sequence. Needless to say if you have a multiple MB text file this suddenly takes millions of file I/O requests to the operating system which is really slow.