The only possibility I can see at this point is the insanely boring strat of doing nothing but turtling to the high techs while intercepting the DL transports. Then deal with the 100 or so ships they'll have floating about, or just bypass them and invade their worlds with speed.
Has anyone come up with a faster way that doesn't induce mind numbing boredom?
In my experience, the DLs are a one-dimensional foe that does indeed force you into a turtle strategy, where you drive for the high-level weapons techs. In the original GC2, the combat mechanics only allowed them to kill one target per turn, which meant that you could easily fight them with a swarm of tiny ships. You still can, but now you need a lot more ships (at least one more than the DL ship has guns).
Other than that, the main ways I've found of fighting the DLs involve gaming the AI:
- They instantly detect and go to destroy starbases (My bug #2), so don't build them except as a distraction.
- They also seem to detect planets that have a ship garrisoned there (My bug #32), so garrison your ships just adjacent to your planets instead of at them.
If you avoid these two things, the DLs will tend to focus on other races more than you, which gives you time to turtle.
- The DL's combat ships are nearly always speed 6, and their transports are speed 10.
- The DLs rarely escort their transports properly.
Because of these, if you get good sensor ranges (Eyes of the Universe, ideally), and good engines, you can station a screen of fast ships to pick off the DL transports.
The AI also cannot deal well when fighting opponents with faster ships (My bug #33). As long as your ships are at least two points faster than the DL ships, you can avoid them forever. This isn't very fun, though, as it means you're micromanaging the movement of all your ships every turn so as to keep them out of the DL's range.
I usually create a small, fast ship called the "Gadfly", and send it circling the DL's home system. Because the AI doesn't understand how to do an area denial or zone defense, you can herd its ships into a single swarm all following the gadfly. The last time I played, the DLs had a couple hundred ships, and just about every one was merged into this huge stack of ships uselessly following my Gadfly, which I kept just out of their range every turn.
Needless to say, gaming the AI this way is rather unsatisfying, especially since the exploitative strategies tend to be micromanagement-heavy. I'd rather see the DLs be a bit more well-rounded, instead of just having an obscene level of weapons tech. The Antarans in MOO2 were a lot more interesting; they were tough, but not unbeatable in combat, they had their own unique techs (which made the very difficult act of boarding and seizing their ships worth the trouble), and there was more than one way of fighting them.