You can absolutely argue the benefits of a GC, and there are plenty of GC'd languages that as you say are great productivity enhancers.

If anything, D should stop pretending that it doesn't have a GC and stop trying to appeal to people who don't want a GC, it's a losing battle. D should just accept the fact that it is a GC'd language and start making the argument for why it's a better GC'd language than Java or C# or the host of other GC'd languages.

The vast majority of C++ developers do not want a GC'd version of C++, but it's possible that Java developers could be interested in a C++-like language that has a GC and good C compatibility.