I seriously doubt the addition of AmigaDE capabilities would add anything of value to any OS, be it AmigaOS4 or MorphOS.
I don't see any benefit to anybody since DE has not really been demonstrated. Most people are at a loss as to what DE really is and is supposed to do. Being dead quiet for nearly four years after "buying" the Amiga name tends to do that. Personally, I feel Amiga has been dead for two years and won't release anything. If that's not true, they sure haven't been trying hard to convince us otherwise.
Why use DE and Ami2D when you can use PTL natively on practically any OS?