He got caught flat footed at least 3 times. He should have been sacked after the first fiasco. He got a lot of good soldiers killed through his incompetence.
His Inchon landing was a brilliant maneuver. Everyone told him it would not work but not only worked, it worked perfectly.
MacArthur believed the Japanese would attack the Phillipines by air and land. He set up a series of scout positions to spot incoming aircraft. Since the system was brand new they were getting a lot of false reports.
MacArthur thinking the Japanese would attack on the day they did, sent all their aircraft into the air so they would not be sitting ducks on the ground. They began to get low on fuel so they checked to make sure no reports of Japanese planes had come in. It turned out they had gotten one report of a sighting. They held the planes in the air waiting for confirmation. The planes had to land and since there had been no other reports they brought them down for refueling.
As luck would have it, the Japanese attacked just as they were landing. the Americans could not have been more unlucky. McArthur basically did all he could have been expected to do.
Only if you believe the Left's version of history.