EPTHe also used mines "broodwar-esque" on the battlefield. As others have already stated, mines are very suitable to expand safely, as the provide good space control and push back early zerg pressure handily. In the later stages of the game, they're also kinda viable, because they both can be used to slow push with a mech ball, and to defend expansions against runbys / backstabs / mutas. (IdrA had to deal with such plays on his stream yesterday.) They don't seem to be good in the super late stages of a game, though.
Overall, the widow mine seems to be a good addition, even though the fact that the little sucker can hit both ground and air, while dealing tons of splash damage, gives me headaches. It's not imba, but you certainly have to play very cautiously as zerg now. Maybe a little less splash damage would be a fair change.
