Well, Les, I'd give Custer maybe a C+ or a B- as a commander, based on his whole career.

His strengths were: tremendous courage under fire, great enthusiasm, a good deal of charisma for leading men into battle, lots of energy and determination, and great tenacity.

His weaknesses: arrogance, over-confidence, recklessness, some dishonesty here and there in negotiations, a tendency to break the standard military rules (he went AWOL to visit his wife on one occasion and got in major shit for it) , and as you point out, an inability to admit to having made an error.

He fought well and effectively in the Civil War, though, and he did so also in the Indian wars up until his disastrous fight at Little Big Horn.

History has judged Custer harshly for one and only one reason: he screwed up at his very last battle and got himself and his men killed.

The Indians of the time admired Custer on a personal basis for his bravery and flamboyant warrior style....but they were quite angry that he had broken his word to them in various past negotiations, and they had sworn to kill him over that issue.