This has come up as one issue for adoption to D. D2.x is on its way, unstable, and D1.x is getting the ax. While Walter has said that the compiler will continue to get support, no one in the community knows what the library support will be like. I came across an article where even Python wasn't chosen for a project because of the eminent release of Python 3. He also dismisses Ruby and Clojure for other complaints people have expressed about D.
-- http://postabon.posterous.com/why-i-chose-common-lisp-over-python-ruby-and I'm not claiming D is in the wrong in its chosen path. This shows that other languages deal with similar issues, but is one thing for someone familiar with a language to not choose it for a project than it is to get someone to look into a new language.
