Contributing can take many forms, and it's not just for developers.
Many of the workbench features were added because the developers thought they might be useful to others (or were very useful for themselves) However, a significant number were ideas contributed by rocket makers and workbench users. The idea need not be fully formed. Often one incomplete thought leads to another which eventually leads to a useful feature.
It need not be a new component type, although it can. Specialized calculators are often simple to implement and there's value to having them all in one place. FreeCAD has various simulation tools for FEM, CFD, and similar. Analyzers for specific problems such as fin flutter are all doable within the workbench with time and effort. If it can be done in software, the workbench may be a good place to do it.
Best of all, you're not required to do any coding. Although if you can feel free!
This may be one of the most undervalued type of contribution. FreeCAD and the Rocket Workbench aren't only for people speaking the same language as the developers. Translating into common and uncommon languages and their regional dialects requires the contributions of native speakers worldwide.
The Rocket Workbench, like FreeCAD itself, uses Crowdin (https://crowdin.com/project/freecad-addons or https://crowdin.com/project/freecad) for management of translations. Create an account and you'll be able to start contributing right away. In addition to providing translations, you can also proof read the translations already contributed. Do a little or a lot. Even small incremental gains are valuable.
Translations aren't limited to the software. The online wiki pages can also use translators. See https://wiki.freecadweb.org/Localisation#Translate_the_FreeCAD_wiki to get started.
Do our icons make you cringe? Think you can do better?
Programmers often make lousy designers, but in the absence of someone with skill we do what we must. Your contributions can make all the difference.
What can be done to improve your experience? It is easy to overlook an accessibility issue when you're not personally affected but it's often easy to accomodate once the issue is known.
See a bug? Open an issue on GitHub (https://github.com/davesrocketshop/Rocket/issues)
Unit tests at this point are minimal, but improving. If you have QA experience consider writing test cases. If writing the code is beyond your reach, open an issue and we can help.
Obviously developers are integral to any open source project. What is less obvious is that you don't have to be an expert.
For new or less experienced coders, selecting an open issue is often a good place to start. If it's already assigned contact the assignee. They are often willing to hand issues off, and to help you work through the problem if you're just learing. Test cases are also a great place for new coders to learn Python, the FreeCAD environment, and the Rocket Wokbench code base.
There are a number of issues that can really be classed as projects. If you feel you are ready to take one on, contact the developers and we can discuss how you can integrate your code with the existing code base, and how that feature or issue should work to maintain consistency of code and look and feel.
Feel like adding a new feature? Open a ticket to use as a basis for discussion. Describe your idea. Discuss with the other developers and start coding!
If you're not using it then there's no point. So let's make this a tool you want to use.