Plugins are currently and will remain global, and although it says the plugins are, 'loaded' there's nothing loading until you actually use the plugin. So, effectively the plugins are only used in the profiles that reference them. Making plugins, 'per profile' means extra profile loading time and yet another user interface.
The only thing that is done when VA launches is that the interfaces are checked to make sure that they are valid, and that uses almost zero resources. So, I must ask what the issue is that plugins need to be per profile?