It's weird, but even though my Spanish sucks and I find it hard to watch local TV, the Spanish in Narcos was somehow way easier to understand for me.
1)It's Colombian spanish (mostly) -- they speak slower and it is considered the most neutral form of Latin American Spanish
2) Pedro Pascal is Chilean but after growing up in the USA had to relearn Spanish.
3) Walter Moura is Brasilian and had to learn spanish for the series -- so he speaks slow.
Basically it's a bunch of slow non-native speakers semi-mangling Colombian spanish. The govt officials are the ones actually from Colombia I believe. The girl that plays the journalist is from PR or Mexico.
Moura's not bad for only having spoken the language for a few months before filming, but even if you're not a native speaker, if you know what a Brasilian accent sounds like you really do hear it in half his dialogue.
Portenos speak very fast, so if you hone your ear here, most other spanish accents are much easier to deal with.
i just couldn't take ALL the narration. When the Gringo finally shut up the series was interesting, but man, way too much narration.