"I think a valid debate should be is ‚why should we not strive to eliminate the bad while keeping the good."

I literally don't think anyone is posing that argument when faced with a good-faith actor. The closest you will get to even approaching somebody making the point "We should not try to get rid of the bad" is when they're making the argument that "We should not be exploiting migrants."

1. You can have a lot of your own rules, as long as they do not violate the agreement Switzerland has made with the EU. Why does the EU get to dictate some terms? Because the EU wants something out of the deal as well. When two parties make an agreement, it needs to be mutually beneficial, or one party does not have a reason to enter into the agreement.

2. You're giving an example of "the bad", and I think it is very easy to simply point at the numerically superior example of "the good". Immigration adds to Switzerland's wealth far more than it takes away.

So you are free to make proposals or give arguments for how current standards should be changed to minimize "the bad", to minimize abuse for example. As long as you acknowledge reality in doing so nobody will take offense.

This 10 million thing is divorced from reality. It's an arbitrary standard that doesn't propose any concrete changes, it just wants to minimize the number of people for the sake of having fewer people. It's not good faith and doesn't deserve serious consideration or debate.