Journalists generally avoid asking for classified information. The belief is that (in the US) a journalist that passively receives classified information & publishes it isn't committing a crime due to the First Amendment. The actual crime itself was committed by the person leaking the information.

Julian Assange actively solicited leaks of information. That's where the espionage claim comes from.

There's not much precedent on this though and making a plea deal avoids establishing one. I am not a lawyer, and this is not legal advice. Generally, precedent is established when someone appeals their conviction, and a higher court determines that the conviction is lawful. Higher court decisions bind lower courts, so e.g. if a circuit appeals court says the law is "X", every district court within it has to agree.

Since generally, you wouldn't appeal a plea deal, there probably won't be legal precedent from this.

That being said, I wonder if the USA will informally say "we got Assange; we can get you" the next time a similar situation comes up.