Interesting insights. I had a friend who served in the army, during the Korea War. He liked to use the M-2 Carbine. During the retreat to Hungnam he singlehandedly captured 7 Chinese soldiers. He was awarded the Bronze Star for it. He was a funny guy, he was a short Hispanic guy, but he literally sounded like John Wayne. He said he came around the corner of a farmhouse, and "got the drop on them", and ordered them to surrender in Japanese. He thought the M-1 was too heavy, and the Grease Gun too incontrollable, but the M-2 was just right. He liked to use it on semi-auto, rather then full-auto. He was actually a telephone lineman, not an infantrymen, but he had his pick of personal weapons. I never asked him, but I would assume the BAR would have been out of the question.
To the point the BAR did the job it was designed to do, a squad automatic rifle. It wasn't a light machinegun, like the Bren Gun. In a WWII context American Troops had the distinction of being the only ones fully armed with semi, and fully automatic weapons. A squad with bolt action rifles was more dependent on a LMG for a base of fire. An American Squad had more distributed firepower, so the limitations of the BAR weren't so serious. In fact later in WWII the number of BAR's per rifle squad was usually increased to 2, and to 3 in the Marine Corps. Rifle Companies got has many BAR's as they could get their hands on. Until the advent of the M-60 the BAR was an indispensable support weapon. The limitations of the BAR are more apparent now because we can compare it to a weapon like the M-60, which replaced it, along with the 30 cal M-2 LMG. In WWII it would have been hard to replace.