I work on a Mac in OS-X. I am proficient in Word, pretty good at InDesign, and a beginner with FM, which I need for a large book (28-30 chapters, 600-800 pages).
The FM layout process sure is clunky in comparison to working with InDesign -- everything feels more rigid and it takes lots more clicks and keystrokes to accomplish anything. The FM text editor is great, and far more stable than Word, but it sure feels and looks dated. I'm trying not to let that stop me because I'd really like it if I never had to open Word again.
So, things I wish an FM upgrade would have:
Easier text flow and frame connection -- more like InDesign, which is very fluid. Viewable text threads so you can see the flow when you need to.
Contrast color grid lines; more options for grid spacing. Option to view baselines.
Movable guide lines.
More ability to customize toolbars and keystrokes.
More freedom to place anchored frames without so many work-arounds needed -- maybe I'm not familiar enough with the program, but it sure isn't intuitive how to get them in the right place, at the right size, and have them stay put. Arranging graphics in relation to text on a page might take me a minute in InDesign, and ten times as long in FM. I often feel like the program is fighting me because the rules are too rigid. Too often I find myself trying to trick it into letting me do something that ought to be simple, like having a graphic straddle a side head and a text frame without knocking out the text or slipping off the page entirely. Grrrrr.
A couple of ideas that FM could borrow from Word -- I really like the "Document Map" in Word for Mac. This is a panel that slides out to the side of the text window that lets you see the outline or hierarchy of the document. It is a great navigation tool -- clicking on a heading in the document map takes you to the text. Also "Outline" view in Word is generated automatically and lets you move blocks of text. I think it is similar to the Elements View in Structured FM (which I'm not familiar with), Anyhow, Document Map or Outline View, or even better, a combination of the two would be really good to have in FM.
FM allows you to build a dictionary of abbreviations for commonly used words and then use Find and Replace to expand them. It's very helpful, but isn't as good as the AutoCorrect in Word that completes the abbreviations as you type. Major time saver.
And of course, OS-X please, please, please!! FM is the only legacy program I still use and the UI is really dated.
Of course, I suppose one could speculate about InDesign evolving into the OS-X version of FM...Just like SGML used to be an add-on to FM, maybe the more robust FM features could be written as add-ons to ID? One "module" could be a serious text editor, (and no, Story Editor doesn't do it, but is that where this is going?). Another chunk could be the "Book" for chapters with footnotes, cross-references, indexes, etc. If they ported over the pieces of FM that are missing in ID, they wouldn't have to reinvent the wheel, and perhaps we'd get a modernized version of FM more quickly.