I'd prefer 1 also. Exactly like double-click behavior.
The main place where I think there would be a benefit from nodes automatically expanding/contracting with one click is at the very top level (i.e. Tables, Triggers, Packages..), because 99.9% of the time that's what I do at that level, and it's the level I click on the most. On child nodes, I most frequently right-click (ie. to edit a package or trigger, query a table, etc.)