Non-orthogonality: Multiple features that accomplish nearly the same result in different ways. For a language maintainer, this is another piece that will have

Non-orthogonality: Multiple features that accomplish nearly the same result in different ways. For a language maintainer, this is another piece that will have to be supported, troubleshooted and documented. The other problem for users is that it gives a sense of confusion and uncertainty (Paradox of Choice) about the correctness of a program that may lead to multiple refactorings that don't add any value. Also, more features require more learning and makes programs harder to understand. The goals of any good language should be correctness and understandability. Arguably, Python learned the lessons from Perl. But there are many different languages, and some are better in different instances. What Nimrod turns into will be hard to say, but Go and Erlang need more competition.