Contributions from all developers are always welcome, so feel free to fork the project and make a PR when you have a change or a new addition that you would like to add. Keep in mind that the code should follow the principles of the existing source and that the addition should not be incoherent with the rest of the mod.
If you don't have the technical skills to add a feature yourself, of you just don't want to write the code for it, you can always use the Feature Request Module to suggest new content for the mod. Suggestions are always welcome and sometimes they can lead to amazing new features, so feel free to suggest whatever you have in mind :)