The GAISE report (Guidelines for Assessment and Instruction in Statistics Education, http://www.amstat.org/education/publications.cfm) doesn’t give large amounts of attention to stem-and-leaf plots. It puts them at level A (the first of three developmental levels):

The Framework uses three developmental Levels: A, B, and C. Although these three levels may parallel grade levels, they are based on development in statistical literacy, not age. Thus, a middle-school student who has had no prior experience with statistics will need to begin with Level A concepts and activities before moving to Level B. This holds true for a secondary student as well. If a student hasn’t had Level A and B experiences prior to high school, then it is not appropriate for that student to jump into Level C expectations. The learning is more teacher-driven at Level A, but becomes student-driven at Levels B and C. (p. 13)
 

I suspect that for young children stem-and-leaf plots might be a bit hard to read because the digits convey so much information and the less detailed dot plots might be more helpful in seeing trends. Also, stem-and-leaf plots don’t seem to lead quite so straightforwardly to later types of graphs.

BTW, the president of the American Statistical Association has a blog post “2013: The International Year of Statistics” here: http://www.huffingtonpost.com/marie-davidian/2013-the-international-ye_b_2670704.html