Making big things takes a long time. The Brooklyn Bridge or Sears Tower weren't built in a day. So, when you're creating the biggest starship ever to come out for Star Wars: Armada, it's going to take time. Unfortunately, with time can potentially come delays, so it takes more time. While I certainly wanted to pick up one of these ships ASAP, I'm going to have to wait until Q3 before I can get my hands on a Super Star Destroyer.
From the announcement:
At Gen Con 2018, Fantasy Flight Games first announced a monumental miniature for Star Wars™: Armada—the Super Star Destroyer, measuring an incredible 24 inches in length and establishing an entirely new class of huge ships. This reminder of Imperial might will strike fear into the heart of any opponent, but Imperial commanders will have to wait a little longer before initiating launch sequence.
We regret to inform you that the Super Star Destroyer Expansion Packfor Star Wars: Armada, which was originally slated for release in first quarter of 2019, has been delayed and is now scheduled to land at retailers in the third quarter of 2019.