Well .. I guess you’d have to define “real XML editor,” but if by real you mean that the editor can open XML files on disk, and write the edited XML back to disk, then it’s as real as any other XML editor that I’ve seen. All XML editors have different features, and you may prefer one editor over another because of its features. But FrameMaker is definitely a real XML editor, because it can open, edit, and save XML files.
I hear people say that FrameMaker’s not a real XML editor because it uses a proprietary binary format and you can’t edit the XML tags directly. The truth is that all XML editors convert the XML on disk to some internal binary format while the file is open for editing. That’s how you get that nice tag coloring and fonts. Just because the XML you’re editing looks like the XML you think is in the file, that’s just eyewash. Granted, FrameMaker doesn’t let you edit the XML structure by entering tag names in angle-bracketed code, but that doesn’t change the fact that you are editing the same XML structure that you would with any other XML editor. It’s just a different rendering of the XML on disk than you’ll see in other tools. (It would be nice if FM provided a “code view” .. I hope that’s added in the future.)
FrameMaker does provide a number of views into the structure of the XML. It offers a “structure view” which is a collapsible tree of element nodes, allowing you to easily modify attribute values and rearrange the elements by dragging and dropping the nodes into new locations. It also offers a “tags view” which lets you see the element boundaries and their names in the content authoring window (similar to a code view, but you can’t actually edit the tags directly).
FrameMaker is actually one of the oldest XML editors on the market. There are valid reasons to use an XML editor other than FrameMaker, but the issue of it not being a “real XML editor” is not one of them.