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User levels are flawed. Each persons concept of a user level is different. You will find the same problems in the user levels as you have now. Some will find each level of the interface either too simple or too complex. When fully user configurable you are presented way too many options at a given time.
There really is a much better solution. Make sure you have a sane default and sane options. Also include a plugin interface for you application. Allow plugins to overide default handling. If you find that something doesn't fit you then install or create the plugin that does. The interface can be as simple or complex as you would like it depending on what you install.
What a enterprising developer needs to do is create a system wide plugin infrastructure that could make the plugin available to all of the applications. The developer of the plugin could decide the rest.
On a different topic, has anyone realized why Gnome and KDE are so differnt? It really is because of the engine. KDE started out with an existing engine. They really didn't have to worry about one of the biggest parts of their infrastructure. They started well ahead of Gnome. Gnome took the fledgling toolkit started by the gimp and has made it pretty awesome. I don't know if Gnome will ever be "ahead" of KDE because while they are DEs they are intended for 2 complely different audiences. I am proud of Gnome though, I think the project has done a fantastic job.