But I still think there are better alternatives now. Depending on your priorities and constraints, OCaml, Go, F#, Scala, and Swift all fit the same description (easier than Rust, safer than C++) and they're in the same realm for performance (slower than C, C++, Rust, etc., but not by much). D could have been there if they had a decade or so with a bigger community.
I am a sucker for language discussions, so let me explain what my problems are with your suggestions.
Ocaml: No support for parallelism, community is even smaller than D, do they have a package manager, yet?
Go: I like generics/templates. If I throw away type safety, I might as well use Python.
F#: I use Linux. The .NET ecosystem is not strong here.
Scala: I don't like the JVM. Also, the Scala compiler is slow.
Swift: Solid ideas, but held back by Object-C compatibility. I don't build iOS apps, so why bother.
I've enjoyed programming in Ocaml, Rust, C++, Haskell, many Lisps, etc. -- they are all excellent languages. But I find (to my own surprise) that I often come back to D when playing with a new design, exactly because of that sweet-spot. I highly recommend giving it a try if you haven't already.