What was his intention when he left the Soviet dock? It said to defect to the United States, did that mean he planned to give his whole submarine to the Americans as payback for the Russian's screwed up (so he thinks) government?
Pretty much. He and his officers were planning to defect (for various personal reasons (Ramius' reason was to punish the communist party for the death of his wife at the hands of a drunken doctor who was a party member)) and hand Red October over to the Americans. That's why the Soviet Navy sailed with orders to sink Red October.
You're a little off on his motivation. He's not particularly against the Soviet system but he understands how the new, virtually undetectable propulsion system upsets the international balance of power and could lead to either side launching a first nuclear strike out of sheer paranoia. At least that's how I recall it from when I read it years ago.