I wonder ...
Our Board is very specific and the users are very creative and many of them try to start their own blog. So why are they doing it? I am quite sure, that they are looking for something of their own. They want to create something
by themselves and especially
for themselves.
That's the way it is and I couldn't stop them, but my website looses their traffic. Most of those users are - how could it be

- very important to the board and their knowledge is in many ways incomparable.
So what I - and I think the rest of you too - really need is a blog system, which is easy to handle and gives the users all the freedom and the possibillities they are looking for.
@stonyarc
I think you are going to far with your mod.
Make it in several steps.
1. only users in a special second usergroup can write blogs.
2. the user joins this open usergroup
3. the admin of the board needs a button to start the process of creating the blog for these users - more comfortable it works automatic by accepting the user in the usergroup
3. the passwords and usernames should be identical and use the DB of the board
4. the search engine of the board should integrate the blogs
This concept doesn't need a full integration in the admincp and doesn't care about the updates of the single users wordpress versions. That's their problem. You can offer help, but I don't think, that many of them will need it.
Thanks for listening and a beer to your health if it's all bullshit I wrote.