Thank you! I see why you'd swap the leaf, but why swap the springs?
The springs differ between the two, and are weighted so that the overall switch stiffness is about the same. If you just swap the leaves you’ll end up with different switch stiffnesses.
I don't know if it's possible to get rid of the scratchy feeling, but I'd like to if it's possible.
You need to disassemble every switch, clear all the dirt out of it (I think an ultrasonic cleaner is probably the best tool for this, but I don’t have one; just swabbing each housing out with an alcohol-soaked Qtip can probably get most of it), lubricate the contact points in the top housing / slider, and then put the switch back together again.
Even then, if the slider or housing plastic have gotten scratched from being used with dust inside them, it might not fully solve the problem, but in general you should be able to make a big improvement.
Takes a large amount of work though.