LAST EDITED ON Mar-06-14 AT 08:36 PM (EST)
 
Mine skills are bad because they share a cooldown with torpedo skills, and furthermore, because they take up tactical bridge officer slots that could be better used for things like cannon rapid fire, beam fire at will, and attack patterns.

Also mines in general are bad because it's a whole weapon slot that's contributing pretty much nothing to your DPS most of the time. If you're in a beamboat, the time you spend getting your mines in place means that some of your arrays won't be hitting the enemy, and in a cannonboat, it's -1 turret slot that could be banging away at someone.

Look at it this way: what's more useful, some mines that might hit an enemy every minute or so, or ~150-200 more DPS from a cannon turret/beam array?

e: Here's my current setup (to view it, log into your own gateway and replace your name up top with mine): http://gateway.startrekonline.com/#char%28T%27Troika@-Troika-%29/ship-equipment