We are getting closer, and little bits here and there are filtering down from various sources. A large thanks goes out to those sources. Also a thanks to tyarlashan for catching this one.
Please remember that these are still considered rumors until we get the book in our grubby little hands.
This information comes to us from Beasts of War
During shooting, wounds must be allocated to the models that are closest to the unit shooting at them. This means if 4 models are wounded from shooting, the four closest models in range are allocated wounds. Apparently you can move them around how you want between those 4 models, but its the closest models that are effected by the shooting.
This means that your melta gunners in the front will often be some of the first to die. No longer will you be able to allocate wounds to the rear of the unit.
With snap fire, overwatch and other changes coming, we are looking at a much more tactical game on the horizon.