Elgg, like many other current web applications, relies on a core or engine which defines a structure upon which smaller applications (plugins) can be developed. Reading posts on the Elgg site from those more at home with the development of Elgg you can see the separation of the core from the functionality that the plugins supply.

Much to my surprise when installing Elgg, that separation was very unclear. Plugins that effect core functionality such as roles sit side by side with plugins that are intended as standalone apps such as forums or forms. As an administrator it is useful be able to have the admin broken up into four areas:
An area of the site that deals with all the core functions such as roles, permissions, registration systems, accessibility, access, database, maintenance and so on An area that deals with presentation issues such as templating An area that deals with the additional applications An area that deals with user and moderation. Separating these areas allows for an instant and clear understanding of how the entire system works and is managed and also allows for a separation of roles to manage the separate areas - one administrator that is tasked with approving users and sitewide/networkwide moderating  of content may not be the person who should have access to the core settings of the site.

I have been a little confused and frustrated that for some application settings I go to a link on the left admin menu, while for a core setting, I may have to scroll down through a list of plugins - and vice versa.

A careful redesign of the administration area, allowing for more complex roles, would be a major benefit not only to users but to developers who would be able to see more clearly how a proposed function may fit into the application hierarchy.