I run a number of site using WPMS and I think this plugin offers great functionality by registering a site in Piwik for each site. It also registers a site for the main blog.
However, I miss an overview of all the sites, including the main blog.
I guess an option could be added to WP-Piwik to track each visit with a separate piwik tracking code on all sites. (One other simple solution is to just add a piwik tracking code to my template),
So, does this request make sense? I would be willing to make a patch if someone can tell me where to submit it.
Also, all the data is already in the db. Would it be better to do this with a Piwik plugin that e.g. agregate a number of sites into one entity on the Piwik side?