Quite bluntly, there is little chance that you'll NOT be the target of the game every time you sit down with this deck. Generally speaking, players don't like having their resources messed with, particularly lands and cards in hand. By aggressively attacking a player's cards in hand, you limit their ability to play the game, which no one particularly enjoys. So, if you want to focus on a heavy discard theme, I would simply expect this kind of resistance and play around it.
Some discard spells that I would recommend that may not draw as much pain for your opponents (and are more consistent) are Necrogen Mists and Bottomless Pit. They do Discard for your opponents on a permanent type that is less easily interacted with.
The lack of Necropotence is definitely odd for this deck. You have a Lifelink Commander and your goal is to keep hands empty. Potence is just really good, particularly with The Haunt having Lifelink. I highly recommend it.
Some discard spells that I would recommend that may not draw as much pain for your opponents (and are more consistent) are Necrogen Mists and Bottomless Pit. They do Discard for your opponents on a permanent type that is less easily interacted with.
The lack of Necropotence is definitely odd for this deck. You have a Lifelink Commander and your goal is to keep hands empty. Potence is just really good, particularly with The Haunt having Lifelink. I highly recommend it.
UB Dralnu, Lich Lord
RBW [Primer]-Kaalia of the Vast
BUG [Primer]-Tasigur, the Golden Fang
GWU [Primer]-Arcades, the Strategist
WUB Primer-Aminatou, the Fateshifter
UBR Nicol Bolas, the Ravager