I'm disappointed about the lack of D, too, since the author gave Nim a try. And it's definitely more mature than, say, Pony (which is an interesting language for other reasons). Also, you can get excellent performance in D, really close to what you will get with C, and that's very often the crucial factor in systems programming.

> Would Swift qualify as one?

For Apple it does.

"Swift is a successor to both the C and Objective-C languages."

https://developer.apple.com/swift/

I definitely consider D one since it's meant to be a continuation to C / C++ without caring about 'backwards compatibility' which is a good thing imho.