Downsides compared to ... All of them: Language is more complex and takes longer to learn. Less community. Less libraries. Python: D cannot be as close to pse

Downsides compared to ... All of them: Language is more complex and takes longer to learn. Less community. Less libraries. Python: D cannot be as close to pseudo code, mostly due to static types. Rust: Borrow checking looks like a nice idea. The question is, if the cost is worth it. As a language, I think D is clearly better than Java and Go. Go has better tooling. For example, go-fmt is production quality, while dfmt is alpha quality.