Here's the thing on controls: When it was designed in the '50's, the average height male was closer to 5'8" with a 32" sleeve, and weighed less than 140 pounds under the age of 25.
The first customers were in SE Asia, the size and fit went over huge compared to a 12 pound main battle rifle.
Stoner also put the controls where they were easy to use while shooting, not where parade and inspection needed them. That was another huge step away from the Palace Guard designs most previous firearms suffered. A thumb operated safety meant you could control it, and not switch it off early because it was a hassle. The mag button, same thing, and with an automatic last round bolt hold open on the left, you don't move your trigger finger while reloading or closing the bolt.
Old school parade guns extend the time it takes to reload, leaving the soldier disarmed twice as long. The AVERAGE soldier isn't a high speed expert three gun competitor, give him a gun that helps him in real life, and he'll get it back in action much faster than other guns that are right hand charged with magazines loaded against a closed bolt.
Those old parade guns finally got the last nail in the coffin with the M16, from then on soldiers (at least in America) knew what was better and worked with them, not what worked for the Platoon commander during Inspection Arms. Look around, Drill and Cereomony units avoid the M16 like the plague - because it's combat oriented, not a parade and exhibition drill stick.
There's a HUGE difference in ergonomics. As someone who's trained years in both, I see it easily. It's the clueless show and tell shooters who still stubbornly cling to old school designs from yesteryear. There's good reason why we tossed the wood and steel guns in the history dumpster, compare the battle statistics than and now. The M16 helps you stay alive longer, and you fight harder when you know your side cares.