Thank you for looking at this in great detail Mark and that all seems like a very useful set of changes! I've got a few more specific comments below, but they're mostly just small details.

2. I'd personally prefer alphabetical order (except Tix, which should be last because it's deprecated) with a note before / elsewhere that a tkinter / tkinter.ttk combination is generally be the best way to create GUIs (perhaps in with the hello world example?).

3. IMO this is suited better grouped with the other Tcl/Tk bridge documentation. I agree we should probably remove Tix from this section, since we're trying to dissuade people from using it.

5. This sounds very reasonable. The accompanying description and list of kwargs was what concerned me, but this sounds easily maintainable. Maybe we could group e.g. the winfo methods and link directly to the version-independent Tk man page for those (https://www.tcl.tk/man/tcl/TkCmd/winfo.html - so we don't need to keep changing the links)?