Maybe add a few examples of existing repositories in the guidelines? For instance I’m not sure that “data munging (In the context of the tools described above. Generic tools such as reshape2, tidyr do not fit this criteria)” is very clear. 
Another point would be to state how to make a “pre-submission enquiry” in the case the package author is not sure he/she has understood whether their package fits? Or saying that opening an issue does not demand much effort so that when in doubt they should submit the package?