Please check the previous discussions on HN regarding seven deadly sins and seven desirable traits of introductory language design [1]. Not sure whether Walter read the paper before designing D because the reference paper is written before D was started, but interestingly D avoids most of the sins and does follow the recommendations. The paper, however, did not mention not having GC as one of the deadly sins but most of modern languages specifically designed for new learners namely ABC and Scratch have GC. The fact that D has GC by default make it very suitable for new introductory programming language (see the 7th recommendation for choosing the suitable level of abstraction).

[1]Seven Deadly Sins of Introductory Programming Language Design (1996) [pdf]:

https://news.ycombinator.com/item?id=28859449