[Roanon]

Even if I am a minority: I like the current mine system. If you allow mines without limit or make sweeping less predictable, mines will become too important. A few cheap units everywhere, and the biggest warfleets are nor problem any more. This will bog down any game infinitely after a certain stage of game where everyone has enough minelayers.

Stalemate games and games where the one who moves is the one who looses suck. The current system which allows you to gamble, but also to be absolutely sure that your minesweeper-protected uberfleet will reach its target undamaged is not realistic, but good for the game.
If there will be minefields without limit, there must be an option like "sweep with care". Sweepers should be able, when encountering a field to big for them, to sweep as much as they can and then stop and continue sweeping next turn - instead of mindlessly ramming the remaining mines.
Also, equipment for detecting minefields before actually impaling on them should be researchable.