Yeah ... in some ways, the Darlocks need to be played like the Psilons: both of them take time to develop their 'core' region and neither one of them have much in terms of combat (i.e., the Mrrshans, the Alkaris, the Bulrathis) or economic bonus (i.e., the Klackons, the Meklars).
On the other hand, I think the Darlocks can be more difficult to play than the Psilons. As a CP, xenophobic Darlocks are inferior to non-xenophobic ones. In spite of the Darlocks' negative diplomatic bias inherent in the game, they should get involved in diplomacy almost as much as the Humans. Industrialist, technologist, or ecologist traits should also be good for the Darlocks.