Comment by alnwlsn
>I would love to be able to specify a chamfer or fillet along a contact edge of two other shapes
Yes, this is how the big cad programs work, they are 'constraint based'. You pick points and lines from other features (or other parts) and add whatever new geometry you want, and a solver fills in the rest. Features build off each other in this way. In OpenSCAD, you are the solver. But, the big programs have a ton of buttons, and scripting, while there, is usually hidden.
It's kind of like the difference between <insert image library> and Photoshop. Photoshop has a ton of useful tools inside, but if all you want to do is crop the bottom 30px from 2000 images, it's better to have a script do that. The scripts can technically do everything that Photoshop can do, but for other things it's easier just to click a few buttons and be done than reinvent the wheel from the ground up each time.