TLDR: How fast should new content (maps) features be rolled out, and how ready should they be? Constant but smaller improvements seems better.
So there is always a compromise: when and what to roll out, how to make it least disruptive vs how to improve the usability and the content quality.
Maps are not really a part of interface because they only appear as part of the page content, which is fully controlled by the community.
content features are not disruptive because they depend on the editors to add them to the pages.
Community has full control, and if it does not like a feature, or if it feels the feature is not ready yet, it will not be used.
I also feel it is very dangerous to delay releasing new features until they are perfect.
In light of this, I feel it is better to continuously roll-out small content-related features without much publicity (e.g. Village pump is OK, blog might be less so), and continuously improve based on community feedback. Once the feature has been out for some time and there is a general consensus that the feature is good, we can start the marketing push. This approach creates less stress on the community liaisons, developers, and servers. Feedback is received in smaller portions and can be properly acted on.