That means CI that spans multiple projects [0], higher abstraction of issue management [1], formal relationships between issues [2] and more.
Having a global wiki or higher level wiki should also be part of that [3], I think.
[0]: https://gitlab.com/gitlab-org/gitlab-ee/issues/933
[1]: https://gitlab.com/gitlab-org/gitlab-ee/issues/928
[2]: https://gitlab.com/gitlab-org/gitlab-ce/issues/4058
[3]: https://gitlab.com/gitlab-org/gitlab-ce/issues/4037