It's not easy, but you can do it. I remember on one occasion we were having an all mine match and got a lot of practice at both avoiding mines and getting them to 'remote detonate' by placing an extra one. Getting them to blow up doesn't take much skill, but getting them to actually do some damage without someone running into them takes a lot of skill.
The 'remote detonation' is made difficult by the timing of the gun. You have to reload the next round, fire, and then wait for it to deploy. So if you try to fire that 6th mine as they pass by your first, chances are you won't actually do damage, as they'll be past it by the time it actually blows.
Currently it feels that mines aren't all that powerful. They're pretty easy to avoid, and only become a real nuisance when you're chasing a ship down (and even then, if you get close enough the mines lose a lot of their effect. You'll either pass by them or have the mine shots hit you before they deploy). They can get annoying when a ship has nothing but mine launchers on certain maps, but given the three dimensional nature of the game, you can still easily avoid them; and the ship full of mines is less able to actively seek out kills or even defend itself when engaged. It can just run and lay mines.
Adding an actual remote feature doesn't change too much, and really depends on how you do it. Does it just blow up one mine at a time? Or all of them? This can make it difficult to get a hit on the target you want or keep a good defensive field respectively. Should there be a range on the detonator? Does an active detonate cause a smaller aoe explosion? Does hitting the detonate happen automatically, or have a time delay?
There's a lot of ways to go about it to prevent it from becoming overpowering.
As for it not fitting the feel of the world, I can't imagine that they do not have electricity or radio. You can see all the lights on the different maps, and ships are able to communicate with each other. Not to mention the Tesla weapons in GoI and the old heat seeking missile launchers in earlier versions of GoIO.