The best option is the creation of a fund that would lead to decent/good living conditions in their own homelands. Personally, I don't know enough about the geography, or how the place could be kept decent to believe this would ever work. It sure sounds good though. Once I try and think about the logistics, though it breaks down, in my opinion.
I'm sure there are many people that would like to stay in current surroundings, close to family and places that are familiar. I just don't know how the radicals could be kept from infiltrating these areas, and whose military would be responsible for patrolling the borders. If the USA was, how much would that cost, and who would want to do that job? It seems like those borders would be open season for repeated attacks.
I'm against allowing the numbers of people that BO or HC suggest to just amble on over to the USA. That's crazy. It has been established that we really don't have a decent method to vet them. However, I think the percentage of danger is reduced if we begin to limit the numbers to women, elderly and children. I think as human beings we need to use some type of risk: ratio method of allowing much smaller, and better vetted numbers of immigrants to come to the US.
I also will re-state my earlier comment that if ISIS and other such groups can identify Christians, and Muslims that don't buy in to their ideology, (and they are being killed and worse daily) we should be able to gather the same intel and start with those people. Maybe instead of waiting for them to come to us, we go to them and grant them some kind of "golden ticket" to the US. It is in no way a perfect answer; I don't think there are any, but if you or I had the misfortune to be born over there, and were a good person, I believe we would do anything we could to ensure a better life for our children and families.
Anyone of almost any age has the capacity to kill. I worry that the ideology has spread enough that there are plenty of second generation terrorists already here, or, the lone wolf types that are surfing the net, looking for a place to fit in and finding it in a terrorist group. If ISIS had the internet presence it has now, would a Dylan Klebold or Eric Harris-type have joined up to feel part of something that in his mind was big and "noble", and meant something? I don't know the answer to that, but I could see it happening.