D4 over a Toerag. In a word, no. Both are so different.
D4 is a more capable off road tool, stunning tow and workhorse which is ideal if that is what you need it for and are willing to pay the premium to get into one.
Toerag is a premium on road 'offroader' if that makes sense. It is capable in the mud as well (but not to D3/4 standards), but like the X5 is designed to be primarily an onroad car.
If I was changing the GTD then I would have a D4, but paying a premium over the Toerag to get a D4 for the wife to get back and forward to work in, did not make sense as the most it will see is an occasional bump up a kerb to park and our winters. It ticks the box of capable all weather motoring, space to get our 'stuff' about and premium feel. A similar spec D4 to the Treg we ordered would be nearly £10k more.
I looked closely at the amarok, but the rear seats are bench like and would not be comfortable for the lad on long journeys. I don't rate the XC90 at all. Driven a few and did not like it. No technical reason, just did not like the drive.