It sounds like a good idea. But I think that a default portal should be created when you add a package.
I have not yet spend enough time in the admin of OACS4, so I can't really say much about the usability, except that is much better than 3x.
Going back to your point when you add a package like bboard, its admin portlet should be inmediately added to the the *big* admin portal. Otherwise you would be adding a lot of complexity for a newbie administrator. The truth is that not many people customize portals.
