Disable Site Delete

That's right. Only network administrator can delete a blog.

Please look into the 'languages' directory of this plugin. you will find the po file. Just translate it and save there as your_locale.mo(e.f en_US.mo)

Yes, there is a plugin by Ryan Hellyer Delete Delete Site but that only removes the menu link and does not actually prevent users from doing it completely(try typing the url and you will know what I mean).

We will love to hear your feedback at BuddyDev

1. No Delete Menu for Non Network Administrator screenshot-1.png.
2. Here is the message shown to the blog owner if they somehow manage to open the link screenshot-2.png