Only effective against cruisers and cap ships for example? That would make frigates more valuable in the mid-late game.
frigates dont need to be any more valuable than they are already, I'm dissapointed in the lack of capital ships as is

Minefields. Since there are definable chokepoints already, such as with dead asteroids and the areas where jump lanes meet, it could be very advantageous to place minefields of various types
they sound rather cheap, given that EVERYTHING is a chokepoint in sins
What about smaller turrets that come in batches - sort of like buying zerglings in starcraft
I like this idea

Well like the title says this thread is for brainstorming defensive structures.
With that said here's my idea.
Missle Launcher platform
Hp: 3200
Armour: whatever is appropriate for it's power
Weaponry: 24 Heavy missle tubes.
Cost: more than the gauss platform but still inline with it's effectiveness.
Torpedo Launcher platform
Hp:2800 ish
Armour: whatever is appropriate for it's power
Weaponry: 8 Ship to Ship Torpedo Tubes
Cost: More than a missle launcher platform but not too much more
Caveeat Torpedos may be to slow too catch a frigate @ full speed and exceleration.
Will add other's too top post with idea Generator credited.
you guys need to take this thread in another direction: how to make turrets weaker, they are really powerful as is, anything other than a LRMS squad has difficulty with more than 2 gauss cannons with a few fighter craft/bomber details as guards.