The Enterprise was also caught in orbit with little room to maneuver. Except for the first strike, the Duras' were behind the Enterprise. While the Enterprise does have full spherical coverage, she doesn't have full power coverage in that sphere. There has been no on screen evidence that the aft launcher could fire a 10 torpedo burst, so that is just way aft coverage is less than bow coverage.
The torpedoes are said to have guidance systems, but I do not believe we have seen then deviate much out of the direction of the launcher on any ship. In otherwards we have never seen a forward launched torpedo circle around and strike a target behind the ship. Even the 1701A with its newly installed plasma sensors never circled around 1701A. When fired, on screen evidence shows a conical firing pattern. Not sure if I'm describing that properly but forward torpedoes fire like this ">" aft like this "<". The aft torpedoes have a larger cone of fire since they don't have to clear the saucer before moving up (relative to the ship). Forward launcher should probably be on, or near, the leading edge of the saucer both dorsal and ventral sides to eliminate that problem. Still could keep the one on the neck, for when the saucer separates