I don't disagree with most of your criticisms, KungFuFerret. I can see the message being rambling because the guy is trying to justify himself to his daughter. His primary concern *isn't* to get the Death Star destroyed, it's to show his daughter that he's not a willing collaborator in the construction of the Genocideomatic 5000.
I disagree, that his primary concern isn't to get the Death Star destroyed. He became a double agent for YEARS, specifically to accomplish that very task. He even says as much in the message. That he knew they would build it without him, but if he was there, he could undermine their efforts.
That's what he wants the recipient of the message to believe. Doesn't mean it's a truthful assessment of the emotional reasons for his actions.
I'm not saying he's deliberately lying, but he's definitely trying to connect with the daughter he misses so terribly and trying to present an image of himself that explains his actions.