You might be right.
Some of the EU stuff is fantastic (admittedly not the novel series that the Sun Crusher comes from). However, I will put the Darth Bane and Thrawn trilogy up against anything we have seen in movies or TV.
The Sun Crusher is
extremely overpowered. It's armour is virturaly invincible. Laser fire does absolutely nothing to it. It was once flown straight through a Star Destroyer's command tower and took no damage (the Star Destroyer did not fare so well).
Offensively, it can destroy entire solar systems by making their sun go supernova. Makes the Death Star super laser seem pretty meek by comparison.
So it pretty much sports the best defense and offense in the Star Wars universe, as far as I know.