>Its array combines lists, and dict functionality. They even preserve order, which is a common need.<
Yes, it's a common need, every week people ask how to sort a dict. Unsorted dicts are probably faster then ordered ones, that probably have to be implemented as some kind of trees (to avoid wasting memory). Around there are some odict (ordered dict) implementations for Python, but maybe they aren't used much. Putting one of such refined implementations inside the collections module of the standard library (Hettinger can probably do something like this in few days) can help, but probably not much. Changing the Python dicts to ordered ones can (probably) be done without breaking old python programs, but such change can probably slow down all the CPython (but I don't know much), so I don't know how much good it can be.
Having a mixed list and dict functionality can be a positive thing for a scripting language that has to be used for quick programming tasks, but probably it's not useful for Python now... I don't know.