It's an interesting, easy read.
The decision does not exonerate Bolton of wrongdoing or liability. In fact, the decision confirms that Bolton has published the book in violation of the law. In future actions, Bolton could both lose book royalties and be criminally prosecuted for failing to obtain final written clearance to publish the material. At the same time, the present circumstances don't meet the legal standard to block further publication. My reading of the decision suggests that had the government brought the case sooner, they might have prevailed, but once "the horse is out of the barn" (copies of the book have been released to the media and others), it's too late for an injunction blocking further publication of the book. The secrets are no longer secrets, the damage is done and injunctive relief cannot alter that fact.
The law and the legal reasoning behind the decision appear straightforward so I expect that Barr will pursue both criminal and civil remedies, both of which would be legally justifiable. Such a prosecution might not proceed under a different president and USAG for political reasons. Likewise, pursuing prosecution will be motivated in part by political considerations... and revenge. If charged, would Bolton be convicted? All bets are off depending on the jury and Bolton's defense strategy. The aspect of this that surprises me is that Bolton is willing to gamble on this approach.
I despise both Trump and Barr, but I believe Bolton should be prosecuted. If Bolton were motivated by concern about presidential lawbreaking, he had an opportunity to make his concerns known earlier and perhaps more consequentially. Instead, he delayed, and the delay seems entirely motivated by Bolton's personal financial interests. As a high ranking government official, the only appropriate motivation should be the good of the country. Protecting American interests may incidentally attach to the publication of the book, but Bolton's failure to report his concerns to the appropriate IG and his refusal to testify before a closed, security-cleared congressional committee tells you everything you need to know about his motives.
Incidentally, I wonder how many will laud or condemn the judge's decision without actually reading the decision.