Yeah, but the part of the wing the cruiser sliced off like butter was about 20,000 meters wide. The FO Star Destroyers are also quite a bit bigger than the Imperial Star Destroyer. Either way the DS would have sustained major damage, to the point where it would no longer be oeprational, especially if the cruisers had pointed their attack at the DS disc.
In the EU there is a text about hyperspace collisions.
“Hyperspace collisions, whether they be intentional or by accident, could devastate or even destroy a planet. Considering the fact that the output of the reactors of many Capital ships rivaled or eclipsed that of a star, and that the energies needed to make hyperspace travel possible were vast, one could unleash a great deal of destructive power on a target. Even if a planet had its planetary shielding up at the time of a hyperspace collision, it could still have the potential to kill millions on a world such as Coruscant just due to the fallout.[4] One of the more famous hyperspace accidents occurred during the Clone Wars, when the battlecruiser Quaestor collided with the Separatist planet Pammant, fracturing it to its core.”