I really would like a nice frontside wysiwyg-editor for the P2 theme. Preferable a light one with only the most basic controls. Tried front-end-editor but not to fond of it´s looks and UX. Plain and simple are key.
WYSIhtml is one that has been getting a lot of love from people these days. See: http://xing.github.com/wysihtml5/
But, 'nice' is very subjective.
I think that the built-in wp_editor can do this job pretty nice.
Sure tinymce is cinda heavy but its already loaded and cached in the browser. So why dont use WordPress native functions instead of using another lib? Look how simple it is to register an editor:
wp_editor('', 'wpse', array( 'teeny' => true, 'media_buttons' => false ));
I think its pretty sweet:
Read more about the parameters and how it wokrs in WordPress-Codex
This question is quite old but the plugin which answers this question is quite new (in fact not finished yet).