when you close your doors to incredibly unfortunate people like the refugees from Syria I do not really understand it. Even Israel announced taking 100 children and their families from Syria and they remain at 'war' with Syria.  
Nothing wrong with better vetting of immigrants from anywhere.
I think his intentions are good , but it probably won't matter. Many 'terrorists'/ crazies are home grown anyways. 
I often wonder why all these people from Muslim countries want to come west anyways. It doesn't say much for their homeland. I guess it is for better life/ education etc. Can't blame them but why not improve their home situation so there is no need to leave. Has any Christian or  Jew ever wanted  to immigrate to an Arab country other than for  a temporary reason (ie work related)? Bet it would be hard to find anyone.