Removal in Pioneer is a tricky topic. Good removal picks for a weekend can be the difference that wins you a tournament, and picking the wrong removal or playing it wrong loses matches. There’s no one trick to having the right answers at the right times, but there are a couple that can get you closer.
The best advice about casting removal in Pioneer is don’t. Don’t put any removal spells in your deck that you aren’t forced to play.
The threats in Pioneer are better than the answers. Not massively better, but by default your reactive plays are made at a loss. Too many of the threats provide immediate value or provide value when killed. Even if a removal spell lines up well against something, it probably isn’t even good against the other half of your opponent’s deck.
Before a removal spell even makes your deck in Pioneer, you should be thinking about how it can be cast in a way that doesn’t leave you behind. Playing removal without a purpose is just declaring you are starting each game with bad cards in your hand.
Is there some threat you have to answer, to the point where you just don’t care if you end up behind on the exchange? Dreadbore almost always kills a planeswalker after it activates for some value, but the alternative play of not casting Dreadbore means they keep activating it and you lose. As a result, everyone plays Dreadbore in Rakdos decks.
Very helpful!