For any Stack Exchange community the meta site is important. This is currently not reflected by the newsletter since it does not include any meta posts. Therefore I would like to suggest that in any newsletter some posts from the respective site's meta site are included.
A strong reason for having some meta posts in the newsletter is to get people involved in meta. I am not sure exactly how meta posts are to be selected for the newsletter. One way to implement it would be to include two to four active meta posts since the last newsletter. The meta posts would be listed under its own heading as the last heading in the newsletter:
Active meta questions this week:
[Questions included just like under any other heading.]