HTML composer:
Did you consider using Fckeditor? I checked the archives
and I saw that there was a discussion about that in Oct 2005, and the
conclusion was that the goal is to support plugging any editor with
plugins
API, what's being developped. What's the status of this?
I used both TinyMCE and FCKeditor and I prefer FCK.
JS interface:
Did you consider using a JS framework? I've been working quite much
with prototype
and after that JQuery. My personal preference is JQuery, based on
experiences.
Rewriting would be a big job, but could be done continuously, during
the process
both packages would exist.
There are some benefits, I think even the code would become smaller, and
pre-created interface plugins could be used. (And the packed version is
just 16k.)