The Front End Editor needs to go ALL the WAY! Give the Front End Editor access to all the Admin functions built into plugins!
People have built plugins, for instance, for multiple Users portal sites. For instance, I have a Rentals site to allow every registered user to post their own rental properties, which they can do from a Front End form. And they can delete and modify their properties from the same Front End.
However, I have a plugin written for the existing WP core WP Admin plugins environment. Up to this moment all plugins with settings that are offered to, say, Authors, to customize their posts require logging in to the backend just like the site Administrator must.
If you are going to all this work for a new "Front End-does-all" functionality then PLEASE PLEASE enable plugins that work in the backend to work with full admin capabilities in your Front End!
In other words, any plugin already written for the standard back end settings and user modifications should work in a similar fashion in the Front End.
As an Admin I can tick the installed plugins I want "imported" into the Front End.
If the plugin gives each User with an Author role some individualized settings (a calendar, for instance) and tabs to go back and forth between "tweaks" or settings in the WP Admin backend then automatically allow these capabilities to show up in the Front End -- expanding the Front End beyond just a glorified "form".