defense ship

As always, it depends on what you are defending against.

agreed. always depends against what /who you are defending against. i also found out at times a well rounded defensive ship (ie one with all 3 defenses) do come in handy when you face multiple enemies and not really at war with any of them at the time. they can survive alittle. enough if you have offensive ships with them. Never as good as ships designed defensively for a specific enemy.

Yeah, you'd get hammered to bits by Disruptors if you tried that in my current game.

What I do is spy on the other civ's fleets to see what weapons they are using, then pick who I want to destroy first and ally with all civ's that don't use the same weapons as that civ. That way you can put weapons and armour on all your ships to easily counter your enemies and not have to worry about your ships being attacked by an enemy which uses weapons you don't have defences against or has armour to block your weapons.

Maybe it's just be, but I'd do it completely differently.

Using two types of weapons on the same ship is bad because the enemy rolls defense against each weapon.

Defense isn't worth researching or building unless it matches your enemy's attack. But since you already have strong defenses researched, using them isn't bad.

Put some engines on it so it can actually intercept enemy fleets.