Please turn off the ajax loading of the tinymce editor.
The performance gain is minimal, but on the other hand it does not work well with other mce plugins, because they are not loaded when the editor is loaded using ajax.
I have spend many hours getting the editor to work well with some tinymce extensions. It works fine when the editor is not loaded as ajax, but it breaks after the 3.0.1 update with ajax loading.
So please either make it an option, or disable the ajax editor load.
I honestly think it is more user friendly to simply load the editor on page load instead of forcing the user to wait when he/she enters the answer field.
It is not obvious for the user that an editor loading is happening.