That might be feasible if the conflict in their home countries could be reasonably said to be over soon. Keeping people in "temporary" camps for 5+ years may not be the best idea however.
Well, with proper integration, fewer of them may turn into criminals in the first place. At the moment they're not allowed to do anything for several months after arrival, unemployment etc. can drive people crazy, especially if it made them go on a crazy journey in the first place in the hopes of getting a job. One idea I liked was that they will be instructed upon arrival that the German courses are mandatory, that they have to take care of their homes here, including cleaning the toilets etc. and are required to do certain community work in return for the shelter etc. they receive here. Failure to comply would lead to a swift deportation.
Deportation is difficult because deportation to a war zone is illegal, but then again if you actually did deport them to Syria, maybe fewer north africans would claim to be from there and then misbehave...
As for weeding out future misbehavers, you usually do most of that by integrating them properly as said above.
And yes, this is hard to do because we already create more poor of our own every year whom we slowly disintegrate from our own society, that doesn't make it easier to integrate new poor people as there are no jobs etc. to be taken.
Then again, if the world were a fair place, maybe they'd see no need to migrate here in the first place.
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