@brass-man Thank you for the very thoughtful write up.
WHAT DO I WANT [DISCARD] TO ACCOMPLISH, AND WHAT IS THE BEST CARD OR STRATEGY FOR ACCOMPLISHING THAT? Discard is first and foremost, disruption. Dredge plays discard very well with Cabal Therapy and it does exactly what they want it to do, disrupt you and slow you down. The next best play is Thoughtknot Seer and Kitesail Freebooter, which play discard engines with legs and those not only remove a card that you get to pick but they put a presence on the board serving as disruption in much the same way that Dredge does it by creating zombies when they flashback Therapy.
IN WHAT SITUATIONS IS [DISCARD] ALREADY GOOD, AND WHAT SORTS OF THINGS MAKE THOSE SITUATIONS MORE LIKELY TO HAPPEN? It is currently working well with aggressive decks that want to disrupt the hand of the opponent while still adding threats to the board.
WHAT'S THE BEST POSSIBLE DECK I COULD RUN, IF I ACCEPT RUNNING/BUILDING AROUND [DISCARD] AS A HANDICAP? Right now it is an aggressive creature based deck.
I want to take this in a slightly different direction. Our format does not ban cards we restrict them. This has 2 possible outcomes:
The card is not strong enough to play as a one of and slowly fades away similar to Thirst for Knowledge and it can be unrestricted when the metagame has shifted from whatever broke the card in the first place.
The card works so well with other cards in the metagame that it is worth playing even as a one of see - Gush, Treasure Cruise, Dig Through Time, Thorn of Amethyst, Lodestone Golem, Chalice of the Void and Monastery Mentor.
This is relevant to examining discard for a very special reason. Discard works in lower formats because there is less variance and less explosive cards. In a high variance format, the cards that are restricted are extremely explosive.
I wanted to discuss this because I have reached a point with the metagame where counterspells are starting to stifle the metagame into a cantrip, flashback, and brute force format.
There are a few methods to fight this and discard was a tool in the toolbox from 2010 but I feared and I was proved right that this tool is no longer good.