Troublemakers should be dealt accordingly...Whatever Syrians or not... Whatever refugees or not...
You do bad...you enjoy the consequences...
One side killing another, is understandable... But Civil war, is another level.
And if the Majority of Syrian refugees were troublemakers... I think TR would have already sent them back or most of them will have been already dead...
Integration, is possible, but it will take time, mostly among youngsters, those under 18-20 years old. Since they grow up with war and made their "identity" alongside Death and destruction, so yes, their behavior will be radical/different according to mainstream social norms.
And Yes, if possible, they should be sent back in their own country... But only if it's safe to return...otherwise they will not follow willingly and problem may arise.
In The End, all those refugees future is under TR decision, whatever they succeed to make/deal something that will push them to return. But with current situation in Idlib... I'm afraid, it's gonna be difficult.
Let's wait and see.