What are people's experiences with Heretics in T1?
Heretics, or what I'll call the "Crimson NT splash" defense, is pretty strong. It's not being used much right now because it pairs best with Clay. Here are some key pieces/strats:
Simon the Magician (TEC) makes NT evil cards CBN unless Peter, John, or Philip the Evangelist are in play. (And most offenses these days are OT)
Sapphira is very tough, especially because there are several EEs she can play through her Prevent - Dissension in Antioch, Hypocrisy, Deceit of Sapphira, and Disagreement Over Mark (although this last one is tossed by Coliseum).
Deluders is a great way to deal with large bands and discard a nasty GE like Peace or Foreign Sword.
The Egyptian Rebel is good for large CBN bands, including to Sapphira for FBTN or to Deluders to remove all but 1 hero f/ battle CBP.
Hymenaeus searches out a heretic and bands to Philetus, CBI by good. Philetus has better numbers and a better ability than the Disciples version.
Hypocrisy is one of the best EEs in the game. The combo with Mayhem has game-winning power, but other perks are: CBN on Simon, defeats mass bands, can be played on Sapphira, undoes The Serpent's paralysis by sending the hero to your hand to reset, and it plays in territory through Moses (CoW).
Christian Suing Another, with its Interrupt and side battle, is a very good card, especially on Simon.
Deceit of Sapphira played on Simon or Sapphira can be a nasty way to ruin an opponent's banding chain.
Dream is great for drawing, or for leading into a CBN battlewinner by Simon.
A lot of the other Heretics are better suited for T2, and I don't have much experience with them.