I don't see any reason why lars-blogger should be made part of the OpenACS core. It should remain as a package available for everyone, of course, but not as part of the core.
"Core" is defined as: "The most important part of a thing; the essence; as, the core of a subject." (Webster's Revised Unabridged Dictionary).
We want to keep the OpenACS core clean and mean. If you want an OpenACS that will automatically create everything for user personal pages, then create a vertical app which will also install lars-blogger.