Most of the work I did at Facebook that actually launched publicly in some form was on Timeline, although other designers deserve much of the credit for the final product. As for the second part of the question, I think it's hard to understand the dynamics of larger organizations from the outside. There are obviously a lot of really talented designers who have done and still are doing great work inside of Facebook, but the nature of the product is such that it doesn't translate into New Shiny all the time. For a product that reaches more than a billion people, it's still amazing to me that one designer or engineer is able to have the kind of impact they're still able to have working on Facebook. But there's a high cost to change for a product like that, it's a highly interconnected system where even tiny changes have cascading impacts. A lot of the work you do as a designer in a large team supporting a mature product system doesn't see the light of day. That's just the nature of the work. It's not for everyone, and it's certainly not the easiest way to get a lot of individual glory in the broader design community, but it's possible to have a really big impact, and it can be really fulfilling.
I love it. I still use Rdio every day and I don't know what I would do without it. The initial launch of the "all-white" version of Rdio on the desktop was a big surprise to me, partly because they did all that work in a very short period of time after I left, so I hadn't seen any of it. It was a bold move, and there were some rough edges, but they've made a lot of refinements since then, and the design language has really matured as they've spread it to more platforms. I think it's great how closely they managed to anticipate where Apple ended up with iOS 7.
I never interacted with Steve directly, but there wasn't a single project I worked on at Apple where his feedback and direction was not immediately and directly felt. Phil Schiller did sit down next to me and take over my mouse once, though.