Bowler is still a very young project. There are many ways in which it could improve and expand to cover more use cases. Below is a non-exhaustive list of planned features that are just waiting on someone to have the spare cycles to implement.
Linting features, such as looking for and reporting lints, complete with recommended fixes from the CST. Supporting diff output in formats expected by common tools, like Phabricator, would make integration easier.
Integration with common editors or IDE's like Nuclide, such as one-click renaming or encapsulation of attributes into properties.
Comprehensive intermediate representations (IMR) for easier modification of syntax tree elements.
More comprehensive set of default selectors, filters, and modifiers.
Reduce boilerplate for executing queries or fixers.
Better documentation for those unfamiliar with code refactoring.
If you're interested in working on these features, please read the contributors guide and open an issue on the Github repo to discuss it in more detail.