Thanks. I'll give your syntax a try. I initially tried to do the hierarchy with a ST3 project file, but it is not configurable enough. So I resorted to symlinked files for now. One slight drawback of this is you need to run ST3 in admin mode, on Windows, to make full use of the plugin. But it works without any special privileges on MacOS and Ubuntu.
The file system that is created is also symlinked. My idea was that it would only contain directories that relate to your project. If there are files or folders that don't contain vhdl or verilog, but you still want in the sidebar, you can add these to the "files" or "folders" lists in the preferences file.
While making the plugin, I have tried to go the Sublime way in the sense of going along with their intended flow. So I have used the preferences file to define any settings related to the plugin. Commands can be accessed through the command palette, the project menu, or context menu. The on_hover command is used to provide pop-ups. A single build entry point is used with a drop down to select any of the provided or user-created tcl scripts.
If you're working on multiple tasks in parallel, multiple projects can be created or reopened in separate windows in parallel. Windows/projects can run any of the build commands in parallel with each other.
A simple way of importing larger projects is to use vendor created tcl. It supports Vivado and Quartus project tcl files. If you export a project tcl through their GUI, you can simply include this one file in the "files" list, and that's all you need.