There have been a lot of threads in these forums about the terminology we use by now.
I think the same goes for this plugin as well.
Could we please change the:
Blog level messages, Edit Blog Messages, Create New Blog and so on,
Site level Messages, Edit Site Messages, ....
Also the variables you use are: %blogname%, %blogurl%, %sitename%, %siteurl% . I don't know how you could handle those. I guess it's a bit more complicated.