"Adaptive primitive default sizes" - anything like that?

Is there any facility or addon that attempts to scale primitives at creation to the size of meshes within the scene?

I realize this borders on mind-reading, but I’d like new cubes, for instance, to NOT be as big as the entire mesh I’m working on – for one thing, this immediately obscures the work. For ME, and YMMV, maybe 50% would be about right.

Ideally, such a facility would have a user defined percentage that would generate new meshes at a fraction of the size of the existing work. The F9 window could have a quick “Use Default” for those who want their 1-meter cube, but also want the user control.

Perhaps such a facility could be built into the current F9 window, along with many other sorely needed options (ie, “subdivisions”).