Clark Goble has a quick summary of his thoughts about Swift:
Here are my initial thoughts. First it has most of the features I’d want in a language. It also incorporates a lot of C++ features like generics and overloading that I think can be abused. However overall I’m very excited about the language. More significantly it really allows a degree of interactive development in Xcode that is startling. (Going by the keynote demo and not anything NDAed)
I really think the best part of Swift is the new development tool. It's terrific fun.
Clark also points to the new JS scripting bridge:
Just reading through the documentation, it looks like an improvement on the AppleScript-ObjC approach but definitely not as interesting to me as Swift and the new Playgrounds environment.