Well, this is a easy seeming application to implement, however, I find it in the realm of almost impossible, and also in the realm of not very useful.

With wordpress, you just point it at a database, and as long as its fully functional, (MySQL, Mariadb) it will work. The problem come in, in that the database has lots and lots of information that isn't the content. Such as where, when, what to publish. What to show to whom. Click tracking...

So, in the end, you would have to write a complex database interface that got the content from the blockchain, and kept everything else local. That kind of split would be a pain in the ass. And the interface (since it is clearly deep inside the domain of WP) is not published and can change at any time. (So you may find yourself completely rewriting this part every new version of WP)

Now, the other part. Is it worth it? If you are a successful blogger, then you need the convenience of having all of your information in one place. You also need to have quick enough hosting to serve your users. Having a part of it not in your control can cause real issues.

WP and Steemit do not seem to be 1 to 1 compatible. (I can't even find a list of which tags are approved for steemit use. And there are all kinds of hacks, like class names, that are used in steemit only)

For me, the easiest thing would be to write an app for WP that would push content to Steemit. Right now, I would just copy paste it in. I am sure someone has already made a cludge that does this.