In the latter case your aim should be to conquer territory, disrupt the enemy defenses and hopefully to cut off enemy supply to certain units. Enemy strength is important as you need to eliminate enough units to prevent a retreat from gaining more than one hex. Thus the Enemy strength variable is dependent on the hex grid. It is far better to attack hexes where the defender have to cover three hexes during the retreat to prevent exploitation, as opposed to hexes where the defender only have to cover one hex. The Terrain variable is very important, exploitation is prevented in Rough, Swamp, Towns and Cities.
Rivers prevent units from continued exploitation.
Especially Rough terrain is commonplace, for example it virtually secures the whole Verdun area against exploitation. This seriously affects strategy as well. Finally the Exploit capability available is especially troublesome for the Entente player. Tanks tend to disappear during the attacks while Canadians usually end up getting mauled in offensive action or by artillery. Where to go is a paramount question.