Please define "productive", doing what, to what end, with whom, at what level of complexity? Your clear thoughts here will be illuminating and worthwhile.
Ok, you're claiming productive in /all/ circumstances? Going to have to disagree there. Also with the tone of that as a response but perhaps you didn't mean it.
Maybe giving those circumstances a bit more thought would be instructive and useful to you. Maybe not. Good luck!
Not at all. For example, if you know C-style programming, you can be productive in D with a pretty trivial investment in time.
> Rust is probably what D should have been in all aspects
While D will likely get some sort of borrow checking, it will not adopt the look and feel of Rust.