i did that in a game for a race and there wasn't a turn that they were not declaring war on someone
i haven't seen that behavior in the drengin, myself. if they're declaring war a lot, it's because they're powerful. the super dominator ships really suck, at least after the first year or two of gameplay. they're only comprable to the most basic ships you can build, and don't get any better unless you improve them.
This gives the Drengin a horde type of gameplay.
EX: You have a dozen, practically invincible ships, while they have about...600 cheap hordes of superdominators. If they manage to take one of your ships, it's going to be a loss. However, you can just keeps blowing the H*LL out of their fleets, but they just keep coming! It's nary a pittance of a loss if you blow up about 10 super dominators. So it is a well balanced IMO. (They have actually done this tactic against my super race

)