MacArthur is not regarded so highly by many liberal academics (aka academics) at all and has been the subject of many hit pieces and books. I'm not sure if even Robert E Lee has had his career besmirched as badly as MacArthur's has been. Finding neutral accounts and actually evaluating him is incredibly rare and difficult, since he is so polarizing that it is too easy to focus on just the negatives or the positives and not worry about nuance. There are real criticisms you could have offered: the poor state of readiness of the army before the Korean war, that he had a court instead of a staff (lol), that he commanded much of the Korean war from Tokyo, his manipulation of the narrative, egocentric treatment of his subordinates to the press, accepting the payment from the Philippines, the highly insubordinate letters to Congressman Martin, or his inability to accept criticism. On the positive side you have his extraordinary intellect, his almost suicidal personal courage, his recognition of the importance of Asia (even if he might have just been lucky he was stationed there), the ability to spot and promote talent, his ability to handle the press, his prescient advice about Vietnam and U.S. strategy during the Kennedy talks, etc etc. Plenty of things you can add on both sides.
Not going to spend much time on such an ideological subject, but some quick points:
-The Philippines was completely strategically isolated and likely doomed regardless. The campaign could've been conducted better of course but their position was untenable.
-The U.S. western pacific operations were conducted quite effectively overall compared to other fronts.
-The transformation of Japan from a bitter, ruined, and defeated rival to a powerful, devoted ally was one of the great strategic triumphs of the U.S. MacArthur navigated a very thorny road that was so easy to misstep, and handled it with superb skill.
-The Inchon campaign (and the delaying of the NK offensive earlier) was one of the finest operations in American history. The execution wasn't ideal but it nonetheless completely reversed the strategic situation in record time.
-Many were wrong about the Chinese intervention, including the CIA and Acheson. MacArthur even did a personal reconnaissance and saw nothing. He was still too cocky in his troop movements, but a lot of what happened came down to Chinese skill. Once disaster struck and the UN position was exposed, their retreat was very well managed.
-Who do you think chose Ridgway for the Korean War field commander role and gave him great authority?