> A lot of common operations, such as arbitrary fillets on various edges, are simply hard to express or do.

As a long-time OpenSCAD user, I don't disagree with you but would also point out that LLMs can now make it very easy to do a lot of this sort of thing while still using OpenSCAD.

I actually find Gemini/agy to be the best of the ones I've tried when it comes to working with OpenSCAD code. And I don't recommend trying to use LLMs to one-shot geometry of anything complicated, but they are great for things like "take this OpenSCAD code and generate a fillet along these edges, abstract the fillet into its own module and make it parametric so I can easily modify the radius".

Granted, selecting a few faces or edges in a GUI CAD program and clicking a button is even easier than that, but only once you've spent a lot of time learning how to use the CAD GUI (which, IMO, are nearly universally very unintuitive until you've spent a lot of time working with them).