This is possible with bitcoin isn't it? What does the added complexity of ethereum bring to the table?

> payment schedules or any kind of transaction that does not function exactly like a one time, full size payment

This also seems possible with bitcoin, but it's also a problem that has already been solved better by the traditional payment system (e.g. netflix debits my credit card every month, why would I use a cryptocurrency solution instead?)

> more ambitious ideas, like the Slock.it ones, involve smart locks that hold funds while granting use to a resource, and only return them after access has been revoked

Can you go into specifics here? I'm not really understanding. It sounds like you're describing a kind of autonomous collateral system, but I can't really think of any practical examples where this would be useful (without bringing human judgement into the mix).