I know there already have been several posts regarding mines, but just to keep the discussion/interest going, these suggestions to make mines more tactically useful are all mine (...) and are based on already available game-mechanics.
Overall considered the stepchild in STO, I firmly believe there is enough life left in mines to make them viable, and more importantly, fun.
The main problem with mines is their long deployment times and vulnerability. I'd like to suggest to make ALL available mines cloak, the same way the Romulan tractor beam mines
already do. These are arguably the most (only?) effective mines in the game, and their cloaking tech is already available in-game.
Currently mines can be wiped by AOE effects like BFAW and CSV and are targetable by NPCs and their pets upon release. Taking that part away through cloak also makes mines 'true' mines - you can now deploy/lay them at strategic points without fearing they will be one-shotted when in range of a hapless NPC. You can plan a strategy around them and lure them or delay an enemy approach.
Mines should have their deployment times increased (halved would be ideal) and ideally Mine Dispersal Patterns
should be instantenous as well - eg you don't activate a mine pattern and then launch mines, it should instead be a single (button) action.
This is also already part of the game via the Gamma Reputation Advanced Inhibiting Chroniton Rapid Mine Launcher
which launch a tad faster.
Faster laying, more effective all-cloaking mines would introduce a new role in the game - the dedicated minelayer.
With many maps having enemies vectoring in certain lanes a minelayer-player could be as useful as a Grav Well spammer. It will be something new, and could revitalize certain (older) ships that players would consider 'outdated' or less than stellar for the usual DPS chasing or Delta prime tanking.
It would also improve the previous mine-friendly reputation and weapon sets.
As a limiting factor (so to not make mines OP) there could be a limit to the maximum of deployable cloaked mine pattern "nets" one could lay, say three, after which the first net is replaced by a fresh one.
Mines would still be destroyed by wide AOE effects like Gravity Well, Tykens Rift, Eject Warp plasma or similar. They could also still be targetable by NPCs/players with innate higher perception to detect cloaked ships - this again would revitalize another mostly ignored ability, stealth detection/perception.
For your consideration
Greetings from The Netherlands,