With all due respect, I think it's your assertion that is off base.
The fact that a toy is scaled at 1/60 it doesn't mean the engineering of that toy will equal the engineering of the current 1/60 toys. You're already getting that in the 1/72 scaled releases. A YF-19 and YF-21 at 1/60 can afford the detail and engineering that the 1/48s VF-1s enjoy. The only thing that would probably suffer would be the pilots. But even then, they'll be able to have legs because of the added room in a 1/60 scale 19 or 21 toy.
You should think of it not in scale but in how big that toy will be in inches or centimeters. Right now a 1/48 VF-1 is 12.5 inches long. You think the YF-21 has to be 16" to be that detailed? When a 1/60 YF-21 will equal it in length. The arms, legs and other parts will equal of a 1/60 YF-21 will equal the arms, legs, etc. of a 1/48 VF-1 in ratio. So, to state that a 1/60 M+ is just as detailed in all respects is just. . . Right.