OK...I'm going to put my combat simulator where my mouth is.
Although I do concede that mods make the ideal model harder to obtain, and some modders attention to this area (I'm thinking the brilliant proportions mod) show that others are aware of the "problem".
The combat engine is heavily weighted towards offensive/defensive bonuses
Now any conquest strategy, whether long term or short term has to take advantage of this simple fact.
To demonstrate the weight try this.
Design a light cruisers with 6 large mount DUC 1's. Now design another one exactly the same with combat sensors 1 and ECM 1. Simulate a combat between these 2 designs, noting the obvious that the ship with the sensors wins most of the time.
Increase the combat to 10 ships a side, noting now the the ships with the sensors with all the time with max losses of 3.
That is the advantage a berserker culture with 15% aggresiveness and 10% defensiveness has against a race with no bonuses in that department.
Not overwhelming but a start.
Now assume we're playing some 2k empire setup. With this its quite reasonable to build a race that is berserker with a 20% aggresiveness and a 20% defensiveness. To facilitate this we may take penalties in cunning (even with non-existant cunning its still quite easy to block intel coz defence is much easier than attack), strength and repair.
The next important bit is your research strategy. Most big time warring starts after turn 30 or so. Your simply aiming to get your to hit and defense bonus as high as possible by that time.
To do this go for
1. Sensors and ECM (obvious)
2. Steath and scattering armour (level 3 in both gives you 30% defence).
3. Training facilities. A fully trained ship in a fully trained fleet is +40 attack and +40 defence. Now this is massive. This is nothing but devastating to the unprepared player.
The other key points are mines and point defence. Mines ensure a big war won't break out too soon (and always build explosive warheads II so scattering armour won't bust your field).
Point defence to negate any missile strategy (if the fact that all missiles seem to target the lead ship didn't already).
Don't worry to much about the fighter..the fact they don't get racial (i believe) or experience bonuses and to get sensors or ecm you have to research levels in fighter means even they'll have hard times hitting your ships.
Shake and bake and prepare to serve nothing but cold fury. Soon you too will be getting those 100 ships dead to loss of your one results that we all know and love.
Oh...this strategy does have a counter. When the enemy is adopting the same one
Cheers,
Askan