Engines vs AI

AIs certainly do research engines, but they generally have a pre-set or scripted sequence in which they research items.  You did not say what the difficulty or AI level settings were in your games.  Those settings greatly affect how quickly the AI can do research.  Also, the game settings for research costs have great effects on what technology the AIs have at any point in the game.

The attack values and weapon type (railgun) suggest that you and the AIs also were not very far down the weapon research tracks, as was the fact that no ships had any defense.

In the example you described, I personally might simply have researched armor.  Against just 18 attack points, one could quickly and cheaply research a few levels of early armor and prevail.

On general warship design, I tend to build engine-less defenders that remain in orbits and fairly fast ships for offensive and defensive fleet use.  Also, I have found the AI designs generally not worth copying.

In fact it is one of the AI weaknesses to not use engines so overtly. His fleets might be maxed in attack, but at their slow pace will never be able to do damage in time. A human player can use this for his own advantage, esp. in Dl you can have fast warships that take down planetary defenders whilst your Troop Transports fly around their fleets and take their worlds. Being faster than your enemy gives you also the ability to evade his stronger ships, and reserve your strength to vital strike points. In the end, the AI will have trashed his money into ships that never will see a fight.

Wow, I didnt know about this issue. Is it less ocurring in Dark Avatar? 

Perhaps the developers should fix this in a future patch, if there would every be a new one. The game still sells well, so they should consider some additional effort?

Take up DL and start a "Battle of the Gods" Szenario. Observe the AI's Troop Transports shoot with insane speed from out of the fog-of-war directly onto your unduarded planets. How could he know they were there?

The same dilemma goes for all the resources and planets on the map.... the AI knows where everything is, and this added to a strategy to built only superfast ships and avoid/circumvent all "lossy" fights, but only head towards those that are surely won will give the AI a much-too-great advantage over the human player.

The AI knows your every move and will have no problem to outmanoeuver you every turn, and this would render the game unplayable.

I see more rational behavior in Dark Avatar at the high AI levels.  The AIs will send an unescorted transport at an undefended world, but not at a defended one.  Instead, they will send fleets to beat the orbiting ships first.

(Still waiting for a Watched Threads page...)

Seconded!