There were going to be mines but I don't know now. The idea is to use the area damage for torpedoes. Remember how in the Borg chase scene that at the range the Cube was from the Enterprise that using torpedoes on the Cube would damage the Enterprise too? That's the only time we hear about it, we actually see torpedoes used at even closer ranges, and we see torpedoes used in proximity blasts only a few times but it would be a really cool feature.
On a side note, if you've played the alpha, you can catch up to your torpedoes while accelerating at warp. We thought actually being able to hit the torpedoes with your own ship and take damage would be a hilarious. You have to act very stupidly or sloppily to make it happen.