While it's true that some languages make some horrors easier to bring into the world (if you take away people's access to the memory, for example, you remove an entire class of memory-related nightmares), in my experience, the key requirement for creating these horrors isn't the language; it's the programmer and the constraints they're working under (such things as inexperience, painful levels of urgency, inappropriate processes, team churn, and so on and so on). People can and will make horrors in any language, and if D becomes the new C++, in twenty years people will be saying the same things about D.