I know that Brendan/Noah (forget which one) joked about Gladio being "another season" of Blowback in one of the episodes of Blowback S2, but I am curious what people would be most interested in.
I do think that a season focusing on Europe (either Italy and the Years of Lead specifically, or US covert operations in Western Europe more broadly) would be a good topic. Afghanistan would be very topical (specifically the rise, fall and rise again of the Taliban), but might be a bit close in content to their season on the Iraq War. I'd also be really interested in a season focusing on an African topic, such as the Congo, or the French/US operations in West Africa.
US involvement in shaping modern Indonesia could be a good one. I feel like it's a topic not often covered in lefty circles despite the massive death tolls and how impactful it was. Like Obama's Indonesian step-father was probably an America liason or at the very least some kind of informant.
There are also wackier stories, like the time president Sukarno slept with a KGB honeypot agent disguised as a flight attendant. The CIA got word of it and since at the time they were staffed by bowtie wearing conplete dorks, they tried filming a sex tape with a man disguised as Sukarno and then tried intimidating him with it. Instead he thought it made him look cool.
I believe there was another instance of something like... Instigating anti-communist uprisings by spreading propaganda about communists being witches who can make your dick fall off. I don't remember where I read that.
The Jakarta Method covers this pretty extensively
extremely good book