I'm happy to live in a post-Alan Kay world, but I think maybe it's time to dust off that sculpture of Dijkstra we keep in storage and move it out into the foyer. Programming is hard; glossing over what makes it hard in the name of doing stuff sooner may or may not help, but as long as we debate it without testing it empirically we're sure to get nowhere.
I have to clarify that my comment was targeted towards current Udacity (other MOOC) participants who wants to learn programming as a value added skill or hobby.
If you want to graduate with CS major and/or want to pick CS as a profession; I do believe you need to have a good understanding on the entire stack. There are no shortcuts to being a good professional and achieving mastery in any field requires committed hard work.
When you introduce concepts such as addressing/pointers(which are typically in hexadecimal) and memory management you add many more moving parts to the mix. In my opinion, abstracting a lot of this stuff away helps lower the number of opportunities on which a beginner can get caught up.
Introducing extreme complexity so early in the process turns off people; they give up easily and (falsely, in many cases) start believing that programming is not for them.
The first introduction should have enough fundamental programming concepts to enable the students to make something useful and tangible, by themselves. As the interests and the objectives grow, they can delve deeper into the domain.
I think with Khan Academy, Udacity and others, we are entering a new paradigm of "Just in time learning". Schools should focus on teaching smart learning techniques, critical thinking etc instead of cramming more and more topics in their curriculums.