Because of the rounding down, fractional Attack/Defense bonus is not very useful in the early game where you only have low Attack/Defense ships. For example, early in the game, I mine one military resource that gives my civilization 15% Attack/Defense bonus. It is useless for my tiny, small & medium ships with less than 7 Attack/Defense value.
Suggestion 1: Increase all Attack, Defense and Hit Point value in the game by a factor of 10.
Instead of having a fighter with 1 Attack & 10 Hit Points, we will have fighter with 10 Attack & 100 Hit Points. The effect on game balance is the same, but the fractional Attack/Defense bonus does make a small difference now.
Suggestion 2: As we research better weapon/defense technologies (i.e. Laser Mk I to Laser Mk II), keep the base weapon size the same but increase the damage slightly. For example, Laser Mk I will do 10 damage & Laser Mk II will do 12 damage with the same size. This way we can have the Ship Auto Update features. We just need to design a ship model with Laser and any newly built ship with this model will have the latest Laser installed. The defense technology should work the same way. Of course, if we got better Miniaturization technology or different weapon/defense type, then we have to design a new ship model to take advantage of these.
The ship upgrade function could have two options with different costs: (1) Upgrade to the latest technology only; or (2) Upgrade to a new ship model. An alternative would be to limit the ship upgrade function to Option (1) only.