Facebook is not vulnerable from a privacy standpoint- that was the reason everyone said that they were moving to Google+. They didn't.
Inability to use buggy poorly-designed extremely complex software correctly is not evidence that people don't care. I'm a software engineer and security guy and deal well with complexity and even so I haven't been able to figure out how to keep my profile both visible to the people I want to and secure without devoting way more time than I have available. When I tell people that they often respond "oh thank god it's not just me".
It's not just privacy; it's the whole pattern. The constantly-changing UX is a huge deal to a lot of people, and so is the general attitude of "you're the product" and Zuckerberg's non-apologies.
Agreed that Google+ botched their short-term chance but it has decent usage and now has a much better first-user experience so if people react badly to Timeline, there is an alternative. In any case Google+ has clearly shown there's pent-up demand for a Facebook alternative. They'll keep investing in any case, and there are plenty of other options coming along. I talked about this back in September in "In Chaos there is Opportunity" http://www.talesfromthe.net/jon/?p=3163