I was thinking of creating a thread in the "Feedback" section, but I think it might be impractical for them to create a user-blog section, considering how much work there might be needed to create such a feature.
It wouldn't hurt to at least creating the thread! It might garner some interest and even if it can't be done, it's at least give you an idea as to why. But I think Xenforo does have some blogging add-ons