Context: I've done a lot of Python development and once upon a time delved into Chutney a little bit. In general I agree that there are some confusing things including inheritance. So, I think giving it some love through refactoring would make it more approachable.
As to the specific DictWrapper issue, I also found this confusing. It's kind of tied into a custom templating system too. I would question whether this is a good idea; there are many templating systems already for Python -- what does Chutney's add that these don't already have?
While re-factoring I would try to reduce the amount of inheritence where the user has to understand it to make progress. For example, any API where a user is expected to override a class and re-write some methods.
I'd have to delve back into Chutney to give more specific suggestions, but wanted to chime in and say that I also found it confusing and hard to read Python :)