Look how high he rates the highly controversial Clark. I think this is more a list of men who were useful to Eisenhower, in his perception of his mission, not necessarily an objective rating.
Having said that, I don't think it's possible to objectively rate commanders in any case. No corps or army commander ever had the same tactical situation, the same enemy situation, the same collection of divisions and artillery groups, the same logistics support, etc, etc, etc. It's all a popularity contest. Which leads me to:
You have a good point, in that Ike would have valued most the army and corps commanders who accomplished their missions without complaint or without demanding more troops and priorities from other fronts. Still, he is incisive about the air commanders and also seems to have a sense for the good fighters, yet not elevating many of them above the senior leaders who held the greatest responsibilities.
That is the problem with Montgomery. He was always demanding that resources be switched from Bradley's army group to his.