FWIW the factory throttle controller on the Y62 (4 modes) is a pleasure to use and harking back to my CRD that thing was a PIA at times offroad over gnarly terrain so a '62 without one would be deadly... literally.
I reckon the CRD would def benefit from an after market throttle controller for 'low and slo' work esp if it is a vehicle that has been tuned up a tad.
The ZD30 issues IMHO are a function of that peaky torque band so the factory throttle is too sensitive down low.
Once a decent tune and/or Dawes/Tillix etc is done to get better low RPM response it magnifies the issue.