One of the things that we should ponder is that we haven't seen that many capships go down in the movies.
There was the ion cannoned Imperial, the Super-lasered reb. ships and the Executor running into the 2nd Death Star. We never really saw capships pound each other into oblivion.
What should be done, IMHO is to do away with the "magic, spontaneous explosion" that occurs to a ship that was continuously hit in the antenna arrays. Capships should be gutted, mangled and given horrible scars, but they should still be in one piece most of the time. A single piece full of holes, streaming air and debris but one piece never the less.
Star Wars space warfare has always been like naval warfare in World War II with the fighters standing in for planes and capships for ships. In this analogue Mon Cal ships are cruisers: good speed, firepower and armor. Star Destroyers are battleships with massive armor and firepower but they are slower and more ponderous.
Keep in mind though that there never were clear demarcation lines to these classes, and the classes were concepts onto themselves with different naval roles in mind. Yes, there were cruisers that could go toe-to-toe with some battleships, and there were lighter battleships that were faster.
As you get to heavier ships, they show and increasing tendency to just keep on floating and going even when the ship is so much wreckage. Battleships were often sunk by their own men to keep them out of enemy hands rather than battle damage.
The one ship in SW canon that would show this tenacity is the Star Destroyer. Remember, that the Republic had a lot of these because they were captured rather than destroyed in the Civil War.
Even in the X-Wing books Star Destroyers are more often lamed or crippled than destroyed.
