WordPress.com post editor replacement

WordPress.com supports post editing via the XML-RPC protocol. There are many editors that support this so you can write your posts on your own computer and post them to WordPress.com (or your own hosted WordPress installation). The better clients are smart enough to sync content, so if you use different editors on different computers they will check for new content (probably also drafts) and allow you to edit that too.

If you find another web-based blogging platform that has a nicer editor, it might be possible to create a “hidden” blog there and send your posts to your WordPress.com blog. I have a client that does this with Posterous because he prefers the post-by-mail functionality there.