First thing would be to simplify #setConverterForCode and #selectTextConverterForCode.
Do we still want to use a MacRomanTextConverter, seriously? I'm not even sure I've got that many files with that encoding on my Mac-OSX...

Do we really need to put a ByteOrderMark for UTF-8, seriously? See http://en.wikipedia.org/wiki/Byte_order_mark, it's valueless, and not recommended. It were a Squeak way to specify that a Squeak source file would use UTF-8 rather than MacRoman, but now this should be obsolescent.