A properly gapped and set up G3 design will have no more perceived recoil than any other rifle of that sort. Some folks think the action is louder than the M14 or FAL, and that could be.
I disagree that it is a myth. This Monday I shot my PTR with 150 grain reloads. Today I shot a 88 round match with my M1a.
Based on my "calibrated" shoulder, the PTR action has a harsher recoil slap than a M1a. And it is all due to that massive bolt and carrier hitting the buffer.
I have a port buffer on mine. This device really reduces case dents and ejection distance. Cases are still ejected way ahead, but without the port buffer cases were ejected so hard and so far, that I could not find them in the grass, and some were dented so hard that I could not recover them.
Bill Springfield did the trigger on mine, and it is as good as a tuned M1a trigger.
As far as criticising the rifle for poor ergomics, I really doubt the military purchasing agents could give a flip about these sort of complaints. It is evident that the rifle was designed with at least primary objectives 1) easy to make 2) easy to maintain 3) reliable.
Cost is an overwhelming consideration for a military who is going to buy $200,000,000 worth of weapons. Nice to have things as “better” ergomics are not going to happen if that feature costs a penny more.
The Germans who designed this rifle had the experience of a real war, one that was fought in the Deserts of North Africa, the mud of France, and the artic of the Russian steppes. A soldier’s life expectancy was what, around nine months? Why try to build weapons that last twenty years if the soldier carrying the rifle will be dead in nine months? Germany found that rifles needed to be built faster than the rate they lost their soldiers. I think Germany lost 8 million soldiers, the Russians 20 million, in a war that lasted close to six years.