I assume that you are quite taken with ole' Dugout Doug, but your brief biographical sketch does leave out just a few aspects of his life & character.
I would not presume to call myself an expert on MacArthur, but I've read quite a bit on him, especially Manchester's " American Caesar", among others.
My belief is that he had great strengths, both as a general, and a man, but great faults as well.
Certainly, after being caught flat-footed in the Phillipines in 1941, he did well in the SouthWest Paciic Theater, basically his own fiefdom, from 1943 on, and I suppose the reconquest of the Phillipines was another accomplishment.
He did a masterful job as de facto viceroy of Japan after 1945, and the Inchon Landing was a brilliant stroke; however, it was all down hill from there in Korea.
I almost forgot to mention that he had a fine record in WWI as well.
A very intelligent, courageous, and determined man, he was also vainglorious, egomanical, and he surrounded himself with sycophantic yes men on his staff. Seemed to have a tin ear when it came to politics as well.
My sense is that he always believed himself to be the smartest, most capable guy in the room, no matter where he was.
Certainly, he was essential to Allied victory in the Pacific, but was he THE essential commander? My vote goes to Chester Nimitz.
As far as lacking naval support, the 7th Fleet under Kinkaid, was essentially MacArthur's navy. he had plenty of air support as well, including USMC squadrons in the Phillipines.
Was he America's greatest general? I would say ONE of them , but not the greatest.
Just my two cents.