So TEC mines are actualy what ppl expect of mines: easy to deploy fields (<-- and this is important) of little exploding buggers. You basicly click and in a slightly random pattern, mines are placed into the area. It makes deployment easy, not time consuming and it is a nice way to make use of all that room your guns and bases don't reach.
With their cost and the fact that the actualy do take real space (cant place 2 on top after all) they form a nice addition and have a limit. The limit being the money you have spent on a minefield which after all is not activly hunting enemys targets and the fact that theres only so much room in a given area.
... are a chore. Not only do they basicly work like missiles, bad missiles at that for they are SLOW and can be shot down, but they als orequire a tedious amount of unit micro. They are much less a tool to bolster a defense than a very idiotic form of suicide bomber attack.
You basicly take a squad of drone hosts, have them always DOCK their stuff and then go to an enemy position to unleash the mine-layer-fighters (seriously how drunk do you need to be to come up with fighters that become mines which then hunt ships, but slower and way less efficient than any form of missile) and then send em right into an enemy formation.
So they basicly are missiles. Missiles put under a stupification ray. And they are slow. They cost nothing yes so what do i expect but realy wtf.... they simply arent mines anymore once they move they become missiles. Bad missiles.
Cost nothing, easy (but not conveniant) to deploy and you can create fields of them, everywhere.
Of course it s a bad idea. At least make them cost ressources.
Indeed im going as far as saying that all factions should deploy minefields like the tec does but with different minelayers.
TEC mines, right now, are deployed by a colony, in the colony area and nowhere else. The mines are build by construction frigates.
And for all intends and purposes: tec mines actualy work in their role without being op.
Vasari mines should also be deploed in fields like tec mines, the main difference being that their minelayer, or rather constructor) is mobile. tradeoff being having less mines per spent ressource than tec.
Advent minefighters would also deploy minefields, but would not require a seperate ship. any advent fleet will be able to plant minefields. allthough the fields will be smaller due to the mechanic of using fighters to do the job.
You click the mothership, click "deploy minefield" in squadron mangement (greyed out if you do not have minefighters) then the target location and the ship will start laying mines. It has to work with shift so you can place them conveniantly. It will cost ressources.
Meaning it will automaticly send the fighters to where they are supposed to be.
Tec mines are fine, actualy. Possibly increase the amount of "space" they take so that minefields in overall will be less dense and it serves as a limiter. theres only so much room in that grav well.
Vasari mines should be more expensive but more versatile versions of the tec mines. still immobile fields but with the option to be deployed anywhere.
Advent mines are the least cost effective in terms of number of mines per ressource spent and take the longest to set up, but having mobile mines can make a big difference if circumstances are right.
And heres the main point: Circumstance.
Kept for TEC, having mines deploed is always a good thing. They cost nothing and they do you no harm. They are always good to have under any circumstance, even if their deployment mechanics are rather.... stupid.
So, make it so that mines are only good if the circumstances are right. A big part of it is giving them a pricetag. Tec mines are not always good. They cost you ressources and youre running the risk that they won't do shit for you.
Thats what makes them balanced.
Vasari and advent mines however are seriously out of whack simply becuase they dont cost you ANYTHING but time.
Make all of them cost ressources, sure make the deployment method different but the outcome should always be:
A number of mines randomy placed into a tihgt area. Like TEC mines.
On a side note: does advent iconus guardian repulsion work against mines?