Aren't they all the same?
Most of them actually are, which is why we look forward to those few with genuine potential.
Dawn of War was original when it debuted, after 4 expansion packs offering the exact same thing people got bored.
Act of War is so original that its popularity really didnt take off. They pushed out one expansion pack to help stimulate interest but it did not help much. Have no idea what else Eugen Systems has made since then.