I used to like OpenSCAD for its simple approach but then I discovered SDF-based modelling with Python made possible with this neat library: [1]. This is perfect if you are a programmer that doesn't know anything about CAD-Software.
That is a trifle CPU-intensive, though. Might work OK if you can get it to work with Jupyter, but seems slow for fast iterations and without an interactive view it's hard to model.
Agreed. The display in Jupyter should happen via some inline WebGL-shaders which would be instant rendering. Also the "marching qubes" algorithm to render the stl is not exactly state of the art (use at least octrees or something) and needs very high resolution to achieve good results.
1.: https://github.com/fogleman/sdf