I agree with some of what Einstein says. We should aim to be a very welcoming and friendly site. It is a fledgling site and we don't want to turn users away at this stage or get a bad reputation. Closing questions should be the last resort. Rather than doing so we should help users to improve their questions.
I disagree about encouraging high quality questions. We're not building a wikipedia of physics, so quality does not matter. The goal of the site is to allow people with questions to find people able to provide answers. If you don't like the question, ignore it and leave it to somebody who does.
I disagree with this closure policy. Users who come here from Physics Stack Exchange are unhappy that their questions were closed there. They do not want to see the same thing happening here. It would be pointless for this site to become a duplicate of PSE - heavily regulated, focussed on rules rather than providing a service.
I do not agree that these closure reasons are good. They are not necessary. I think that we should leave it to users to decide for themselves if they want to provide an answer. If they think the question does not show enough effort, or is not clear, they should post a comment or ignore the question. One group of users should not decide what other users can or cannot do.
As Einstein says, closure should be the LAST RESORT. Something that happens only in extreme circumstances. It should never become routine, for routine reasons.
Comments on the closure reasons :
DUPLICATES : Does it really matter if the same question is asked multiple times? The goal here is to provide answers, not to build a reference library like wikipedia. Searching for duplicates is time-consuming and difficult without a good cross-referencing system. If somebody wishes to point out a previous answer, fine. If somebody else wants to copy and paste an old solution and claim credit for it, fine. Why should we care? As long as those who ask and those who answer are satisfied, why should anyone else interfere?
NOT ABOUT PHYSICS : What are the limits of physics? Who decides? Physics overlaps with engineering, chemistry, biology etc. Every other subject. Let the users decide. If they cannot answer it, they should ignore it. If they can apply physical principles to it, it is physics.
TOO CONCEPTUAL : Who decides? If we think so we can post a comment recommending the user re-post on Physics Stack Exchange - but this decision should be left to the user. If we disagree we can post an answer. If the question remains unanswered, what harm does that do?
NO EFFORT : So what? Personally I like to see effort, I prefer to give hints, but I don't think I should be allowed to impose my standards on other users. The questioner may not have any idea what to do. How can we judge?
PURELY MATH : Suggest posting on another site. Or answer it. Let users decide for themselves whether to answer. Even if it is purely maths, somebody may be able to provide an interesting solution using physics.
TRIVIAL MISTAKE : So what? As with duplicates, we're not writing an encyclopaedia. Point out the mistake and move on. Few questions will be looked at again. If you want to save the best, archive them and delete the rest after say 3 months. But don't close active questions.
UNCLEAR WHAT YOU ARE ASKING : Says who? If you don't understand the question, post a comment asking for clarification. Leave those who do understand it the freedom to answer.
VERY LOW QUALITY : Ditto. Post a comment suggesting a suitable edit. Or (if you have the privilege) edit the question yourself.
SPAM : Now this I agree with! If it is not asking a question, it is not welcome.
So in my opinion, the only valid close reasons should be :
NOT A QUESTION (spam, rant, etc)
INACTIVE (for the last 30 days perhaps?) WiTH NO ANSWER
Both these should not only be closed, they should be DELETED.