I agree with @elcste here. Some time ago I filed an issue to launchpad requesting for the settings dialog of the extension to be exposed by default because I found it unbelievable that Ubuntu developers decided to suppress such a rich functionality that they got “for free”. Then I read the superb posts  by Didier Roche describing the rationale for the (then) ongoing effort to move the Ubuntu desktop from Unity to Gnome. After reading that me myself immediately returned to launchpad and closed the issue. Ubuntu decided to provide some basic functionality and the fact that a much richer extension is behind that functionality is just a matter of implementation; nevertheless, the developers have been sensible enough to keep this implementation as close to upstream as possible. Even tough, there are still bugs with autohiding; for example, the dash overlaps icons in the desktop, which AFAIK is hard to fix without upstream changes to the extension API. And adding new features combinatorially increases the complexity of what has to be tested. I prefer Ubuntu developers to focus in providing a robust, maybe even simplistic, core of features. Then, if you’re feeling adventurous, there are extensions (which, in this case, happen to be exactly the same that’s already included -although deliberately crippled- in Ubuntu).
Also you can use dconf-editor to access the full set of options of dash-to-dock, even without installing the external extension.