I'm curious as to why you think suttas should come after people have the basic concepts understood?
The best introductions to the Dhamma that I have found tend to explain the concepts in parallel with the suttas, blending Buddhavacana with modern commentary.
My opinion is partly based on the talk with group members and partly on pure statistics.
At the site down from my signature, which I've maintained for last 9 years, there is a Tipitaka section with about 600 suttas.
Number of visits of those pages can't be even compared with the number of visits of some texts from the Introductory section of the site.
For example, Sh. Dhammika's "Good Questons, Good Answers" or Q & A with Venerable Kusalo.
I assume that frequent repetitions are the main obstacle for newcomers. And also it is difficult to get the whole picture of the teaching without knowing exactly what suttas one should read and in which order.
This of course doesn't mean that the materiai l'm talking about shouldn't have citations from Tipitaka, to support the modern explanations.
On the contrary. Good balance between these two is the best. But sutta's alone don't look to me too promising.
And the third reason. Suttas don't have questions and assignments at the end.
Which means I should make them.