For me, the best combination is the probability of sweep and various types of mines.
Right now, the mines only do standard damage.
I'm thinking about mines that destroy engines, shield generators (emp/ion), master computers (virus), eat resources, cloack systems, etc.
With various types of mines and only a % acuracy in sweep, the minefields can be real dangerous...
Right now if you can constroy a sweep with 20 level V sweep, the minefileds are no more
