There is no perfect theme. The theme with all the features you need and no features you don’t need is a myth. That’s why Longview has been built with modularity in mind. Adding and removing features should be simple and straight forward whenever possible.
Many of the theme’s features can be enabled or disabled from the settings.php file. This (as well as most other files) can be overridden from a child theme. Many features can be disabled simply by unhooking them from the action hook to which they’re attached. Template files are named according to the standard WordPress naming conventions figuring out which files to add, remove, or edit is easy.
Using the Sass preprocessor for CSS allows even the CSS to become modular. Many repeated patterns have been moved to placeholders and mixins so they can be easily loaded when needed, and left out of the final stylesheet if unused.