D certainly has made a few mistakes and having a non-free backend in dmd was one of them. I doubt this could have been avoided though. It was just technical debt, which Symantec now graciously payed off. I have great respect for the Rust people, because it seems they do everything right so far.

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.

yes, ocaml has opam as a package manager now. the community has also grown quite a bit recently.

Sure, but it's not just about whether you fit in the range or not, it's about language design and tradeoffs. Not everyone will appreciate D, but I really think it hits a sweet-spot of language features that I haven't found elsewhere.

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.

That's fair. I love Scala but hate the JVM and all the compromises Scala has made to shoehorn itself into the JVM. Even though there is now a scala-native, I'd still probably not use it until it matures to the level that D is at, and D (or OCaml) would probably be a better choice for me for those usecases.

I recently invested in learning Clojure, enough to get some practical things deployed, but I am far from being a Clojure advanced developer. I wanted to learn a Lisp dialect and am glad I chose Clojure. Rich Hickey is a guru. I don't have any gripes with Clojure but I'm not too deeply invested. Several years ago I was also enamored with Julia, which I was investigating for CPU intensive programs, but never had the time to commit and I was concerned about Julia being too youthful and possibly not getting enough traction. Should I learn D for CPU intensive programs? Also, with Clojure I can make use of the many Java libraries for I/O due to Clojure's good Java interop. Does D have the analogous benefit of tried and tested I/O libraries? Thanks for any suggestions, D has me intrigued.

There are many languages that fit certain general descriptions, but that doesn't mean that the experience of using them will lead me to think they are at all comparable in terms of how well they help me solve the kind of problems I face. Go and Scala - I somehow dont think they are close substitutes for each other. The kind of person that likes D's generics will not be the kind that is ultra happy with Go. The kind that likes the short learning curve and plethora of network libraries in Go might not be thrilled by D early experience. It all depends.