Based on the thought of secrecy...what do you think of the policy about wizarding and muggle worlds not to mix?

I think that the policy is sort of clever, I mean if Muggles found out about magical people, either they would have started burning people again, or getting magical people to run around after them.

I agree, to a point. And here it is; muggles are different than they were back in the Salem days, so perhaps a new Secrecy rule can be put in place. Only tell those you trust implicitly, those you know you can tell anything too. Have severe rules in pl ace for those who go doing magic in front of the muggles, but allow magic in certain extreme times. Like let's say a building is burning and the fire trucks are still miles away. You could be llowed to magic the people out of the building then putting on a memory charm to let them think they got out on their own.