Hi!
| Remember that defense and attacks are a number rolled from 1- whatever it is you have |
It seems this is not entirely correct:
weapons roll from 1 to their max,
defenses roll from 0 to their max. Proof: attacks on the ship wihout defenses always do at least 1 damage, never 0. 1-point atacks on ship with 1-point defense
do cause damage sometimes.
| Q. If you have some space left in your fast offensive ships, why put any defense on it rather than yet another gun? |
Because enemy still fires back on one of my ships, and I hate losing ships so cheaply. So if I know what I'm fighting, I put on my ships so much defense to match their average ship. That's quite easy with medium hulls.
| Definitely think there should be some sort of initiative calculations here |
... and weapons range, and additionall computers for better init/higher accuracy, and combat speed, and
... and you'd get Stars!

My suggestion: don't. Creating a proper (counter)design in Stars! is almost a science - overly complicated for a casual Emperor. I quite enjoy simplicity of the ship design here in GalCiv.
BR, Iztok