Almost 30% by damage, mainly because of the concussion missiles. But if you're firing on ships that are, at most, half of your length, that kind of becomes moot. I think you're missing the perspective here - these classes weren't intended to fight each other, they were intended to combat Rebels. Perhaps the Superior design was drafted significantly earlier when there was no other option.With regards to Executor/Super, I'd go with the Wookieepedia line, if for no other reason than armaments. If you look at it, Super has something to the effect of 40% of Executor's length, but only 20% of her weapons emplacments. Even allowing for the fact that a smaller ship wouldn't be expected to have the corresponding percentage of weapons of a larger vessel, that ship looks undergunned to me. Building it would be a waste of time.
I know what Wookieepedia says, but the fact is that the plans still existed and could have been used. I guess the reasoning behind this thread is that 19-km dreadnoughts should not have been as disposable as they have been in the canon, so some of them clearly have to be the other design. I mean, come on Rebel Assault 2, there's no way a lone TIE Phantom could blow up an Executor when hundreds and hundreds of torpedoes couldn't .The name "Super-class Star Destroyer" was invented by Imperial Navy officials and used in its budget requests to the Imperial Senate during the design and construction phase of the Executor-class Star Dreadnought. This ruse was made to hide the true nature of the class, even going so far as to understate its size and armament, so that oversight committees would not discover its true role.