BP has too many unconnected, moving parts

I wish to design a simple way for users to use either groups or blogs or categories. It is too confusing to go in all directions and no one direction seems to address the whole problem. The problems are:

1. Groups allow group sign-ups and email control but they do not connect to blogs. (I don't trust the WP group-blog plug-in.)
2. Blogs have no blog sign-ups or blog avatars.
3. Forums is waiting for the new forum plug-in.
4. Categories do not allow page-type selection or avatars. (Scholar does not allow page-type selection for categories.)

In a few cases, I need separate blogs. Otherwise, categories may be a way to separate discussions on the main blog.

What is best way to let users blog and comment in several pre-assigned categories?

Do you have suggestions for good ways to structure a site to accomplish these goals?