No! Radians is the SI unit. I would possibly also accept fractions of a whole rotation.

The arbitrary factor of 400 (or 360), is simply not helpful for machine calculations.

What can I do to convince you that including an additional (2 PI)/N or N/(2 PI) factor into every single angle calculation you will ever do is a complete waste of time?

At the very least, you could take out the arbitrary N.

100 gradians is 0.25 rotations, or PI/2 radians. 30 degrees is 1/12 rotations, or PI/6 radians. There is no advantage whatsoever in multiplying everything by an arbitrary scaling factor that is not based on PI (or TAU).