We don't want to use ES too much as Graylog should still work when ES has some problems. It's currently the default output but that may change in the future for

We don't want to use ES too much as Graylog should still work when ES has some problems. It's currently the default output but that may change in the future for special use cases. That being said, we're aware that many people don't like the dependency on MongoDB and we'll work on that.