It is lore friendly, star destroyers were known for their speed, and of course A New Hope begins with a star destroyer managing to at least keep up with a Correlian Corvette.
Take out the engines first, and then you can hit and run to your heart's content.

pah, the must´ve not come out of hyperspace too close to the ship and tractor-beamed it... Vader wouldn´t fail a maneuver like that...
Yeah, well. You might be right. But my masochistic self cannot keep up with the ISD spam on extreme. I´ve given up after stacks of 13 ISDs started suddenly roaming the galaxy map. (same with playing empire on extreme, had a perfect run until week 25/27 and suddenly all hell broke loose. You surely upped the AI-game the last few updates.)

Bombers are too slow and take too long to turn to stop rushing ISDs.

24 X-wings properly tasked can take down an ISD's engines and shields in one pass and quickly move onto the next. (6 per shield gen. 4 per engine).

ISD spam against a load of x-wings is suicide,

The Imperials have no real answer for lots of X-wings. The black sun, however, lol.