Pointed Discussion

Instead of making opponent discard, you force them to put cards on the library, which hinders their time. This is, in fact, an underestimated ability by most. If you can force your opponent to draw cards they already have but couldn't cast (such as expensive cards, or a piece of their combo), it's pretty much as good as getting extra turns for yourself. Don't forget that in an LD deck, this also prevents them from getting to the lands they desperately need.

Stunted Growth gives more bang for your buck. And its green!
Also, Plow under saw some tournament play.

Kind of like plow under, but not as powerful