According to the announcement post, the developer wants the game to be "in a place where it's able to take care of itself."
"Over time, our focus has shifted to updates that not only help maintain Guild Wars but help the game maintain itself," the post reads. "With this focus in mind, we'll no longer be releasing any new content for the live game except in support of automation. Our goal is to get the game to a place where it can continue to run and be available to all of our fans. We have a lot of love for Guild Wars — it's the game that made us what we are today — and we want to continue sharing it with everyone!"
Under the automated additions, players will no longer have to wait for new map selections in Automated Tournaments, and weekend events will now run for a week at a time. A team will still "be around" for critical fixes or crashes.