What GUI based WYSIWYG HTML Web Page editor is available, if any, for NeXT? Was it Create the only app to make web pages?
If we are talking about WYSIWYG, then yeah, Create was pretty much the only application.
For OPENSTEP, there is Create 5.2.1. I believe Create 4 will work on NEXTSTEP 3.x, but the thing to keep in mind is that versions before Create 4.x didn't include the ability to create web pages.
The other option would be something that converts RTFD files to HTML/HTMLD files. These would be simple web pages in the same way that RTF/RTFD files are simple page layout documents. Of course Create 5.x includes a service for converting RTF to HTML in other applications (I use it in TextEdit all the time).
The thing to keep in mind is that even the best WYSIWYG web app can use some help... and the best code editor is OmniWeb 3.x (it includes colored text for tags, live redisplay, error highlighting and reformatting to make work easier).
If you are going to buy Create 5.x you need to contact Andrew Stone directly so he can make you a license string. The Create 5 license string will work for both OPENSTEP and Rhapsody (though not at the same time... if you are using it on one system, you'll have to quit out before starting it up on the other if on the same network).