I had a dog for 11 years that was unpredictable around kids and men. For 11 years I worked on reinforcing positive encounters - but I had to supervise everything and I was so close to ol' Max that I could read every movement, posture, eyes, head etc...
If I ever felt or saw anything that was unusual - I immediately removed him from a situation. When unknown kids came to our home, Max was not left with them.
If he ever bit a child???? It really would depend on why he bit, and how severe the bite. I would not jump to a conclusion and destroy him unless I understood why.
In saying the above, if the conclusion was unprovoked - as much as I loved my Max, I would have done the responsible thing.
If you get this sense RottieLover, then you must take precautions immediately. Never ever leave him unattended. Your daughter is growing up now and will be inviting friends over. Ensure that you teach her to never let anyone in your home without fair warning so that you can move him into another part of the house away from the children.
What concerns me the most about what you posted here and several times prior is that he has a high prey drive. If this is the case, young children running and playing normally will be a problem.
I would try desentizing him immediately. Put a muzzle on him and start walking him near playgrounds but at a safe distance. Ensure that you leash train him everyday and do not give him one inch...not one.
If you need more information on this very serious topic - you know where to reach me.