So I'm looking around other projects [see Research Links at bottom], and if I'm actually going to write this software, I want to go from 0 to over the "basic modelling software ceiling" in features as fast as possible. Features that most all CAD software, big and small, would be able to do. Think things like doing a difference (Combine Cut for those who use Fusion 360) between a cube as the main body and a sphere as the cutting tool. If the project doesn't get further than this hypothetical ceiling and ends up being abandoned, there's almost no return on investment for me since I could've used those features from day 0.
What I need to focus on are all the features that would allow me to actually port over my Fusion 360 designs. With the perspective of looking at the project as if it wasn't mine, I'm currently writing a list of features sorted and rated from 1 - 5, 1 being "That's a nice to have feature that exists/doesn't exist in Fusion" and "Dead on arrival. What other options are out there?". A 1 feature would be some node based workflow for NURBS (The Fusion 360 workflow isn't history based so I never really used it) wheras a 5 would be the ability to use components. 2 and above are features I've actually used or wanted, like a history based Move Faces command.