I don't know what the complications are secifically but this is what they say
here.
https://sourceforge.net/p/cdesktopenv/wiki/LinuxBuild/
"CDE on Linux is not yet to the point of being simple to package for
distribution or a relatively simple to compile from the source archive."
Lack of interest or the port is not ready for primetime yet.
I really like the look of Motif decorations. If you use a dock with Xfce, it
will be functionally very similar. Remove the panel and start app from
desktop (workplace) menu with the right click of the mouse. I wonder if the
native apps dtterm and dtfile work without the full desktop in Xfce. I guess
they need the mwm Motif window manager to work.
I attached a file with the standard CDE XPM and XBM backdrops.
