Hi everyone!
I've been working hard on drastically improving modding support, and there's a good chance the next update will introduce a lot of new modding capabilities.
What am I working on right now?
The WorkshopTools application is getting a brand-new Project Editor—you can see it in the screenshot below. Its interface is very similar to the Unity game engine, so if you're familiar with Unity, creating addons will feel much easier.

In the Project Editor, you'll be able to:
Import sound files, textures, and voxel models, modify them, and more.
Create custom items, weapons, and vehicles, then export and publish them to the Steam Workshop.
Design and build your own levels directly within the editor.
When is the update coming?
The next update is planned for March and will introduce the Project Editor with ability to create melee weapons and guns. If I have enough time, vehicle creation will also be included. Level Creation will NOT be included in the march update.
I'll continue expanding and improving the Project Editor based on your feedback. Stay tuned, and let me know what features you'd like to see!