I think Peter Collins wrote the article for Flight before he had any formal role with Grob - he was/is a staff writer for flight, amongst other things. Maybe he got a job with Grob on the strength of his enthusiasm for the 120!
Looking at it, it seems a sensible progression - the cockpit avionics are common with the T6, and it can have its performance/features restricted to suit earlier students.
I am intrigued to know the future of the Tutor fleet. They are very cheap to operate for the perceived benefit. And, after all, the RAF ran the Chipmunk fleet for many years mainly for the AEF task - will they be retained just for this/UAS?