@McPherson excellent analysis. My one point of disagreement is classifying Halsey and Arnold as duds. Arnold was a competent officer who led the USAAC through a massive expansion, saw it transform into the USAAF, then into it's own seperate branch. He wasn't a genius, but he was competent.
I had to spend some minutes to reflect on these two men. I try to be fair, to put my PoV in their time and place, understand what they knew, what they believed they knew and what limits they had because of it.
For Arnold, I have to say that his air staff let him down on more than one occasion. He was not as badly misfocused as "Bomber" Harris on ineffectual strategic bombing "strategies", but he did make some huge mistakes. I think he was inflexible when it came to AAF policy, he did not listen to his op-art guys, especially the tactical aviation shop and he did not understand or figure out what the operating forces reported back. I'm not so much concerned with the technical side that he personally goofed up, such as the jet program, a replacement bombing sight, the Wright corruption problem, the P-38 debacle or the B-29 disaster. I'm more concerned about his blindness to what he saw in the op-art. By 1941, he should have known that sending in bombers without fighter escort or killing the enemy air force was not going to work.
Halsey, well, he made the right call more than he made the wrong one. He gets hammered, rightly, for his decision to take off after the IJN carriers at Leyte Gulf without leaving a blocking force behind. However, even that decision isn't really wrong. The entire war up to that point had taught the USN that carriers were the most dangerous enemy and to handle them first. So in the abstract, without hindsight, he wasn't wrong for doing what he did. Granted, he should have left his proposed SAG behind, but still. His only other major fuck up was trying to take on that typhoon. That was just boneheaded and stupid of him and he got lucky that more ships weren't lost.
For Halsey I am a bit more forgiving of his mistakes and less of the man. He was a leader that men would cheerfully storm the gates of hell for. You need men like him. But you also need a strong cast of subordinates and a staff who know what they are doing. At Guadalcanal this proved out to work. The supporting infrastructure of leaders and staff who could cover Halsey's weaknesses was there. He still bungled the Battle of Santa Cruz, and Rennell Island and some of the CACTUS operations he ordered were just criminal in the wastage of pilots and I also blame him for Wasp. Still, given what he knew, these mistakes can be forgiven. Even Leyte Gulf and the typhoons can be forgiven. What cannot be forgiven is his actions after his mistakes. He alibied, lied, and ruined other men for mistakes he made and did not stand up and accept personal responsibility for the commission.
So I still harbor hard feelings about Halsey. I cannot help it.