There are 5 ways to abuse Wierding:
1. "My opponent must stop all my cards"
In this situation you have a permanant effect in play that means you get an effect out of every card, even if it`s a basic land.
eg. Spellshapers - Tonic Peddler, Arc Mage, Stronghold Biologist/Machinist, Cursed Scroll
2. "Discard it if you want - I can use my graveyard"
In this situation you have recursive effects that mean you don`t care if they pay 2 life or not.
eg. Hammer Of Bogardan, Nether Spirit, Phyrexian Grimoire
3. "I`m not actually DRAWING the cards"
This is a hard one, only a few effects do this, but if you are 'taking these cards into your hand' then they cannot pay life to stop you.
eg. Fact Or Fiction, Impulse, Scroll Rack
4. "I`ve got lifegain or card-drawing"
Even if your cards aren`t better under a Wierding than your opponent`s cards, simply by drawing more cards you force your opponent to send life faster than you. Alternatively even a moderate lifegain effect is enough to mean you can stop twice as many of your opponent`s cards as he can stop of yours.
eg. Ophidian, Jayemdae Tome, Fountain Of Youth
5. "You`ve got three turns to find a Wrath"
Wierding can also go in an aggressive deck in the same slot as Armageddon or Parallax Tide - youg et an edge on the board, then pay 4-10 life to stop your opponent from recovering before your creatures finish him off.
In any case, it is crucially important that as many cards of yours are going to make your opponent pay 2 life to stop them. They don`t have to be amazing, just so long as they will cost your opponent a card if you play them - eg every removal spell he lets you draw is 2 life you don`t have to spend on one of his creatures. But every Fertile Ground you draw is wasted. You only need a 1/1 in play with a Wierding to grind out a win - the tiniest board advantage is locked into an eventual kill by the Wierding.