ORIGINAL: Gil R.
Actually, Barlow's ratings aren't random -- they're based on this bio:
Maj. Gen. Francis Channing Barlow (b. 1834, d. 1896). A graduate of Harvard, Barlow practiced law in New York prior to the outbreak of the war when he enlisted as a private in the 12th New York. By the Peninsula Campaign, he had risen to the rank of Colonel and was later seriously wounded at Antietam. Appointed a Brigadier General two days after the battle, his brigade was routed by a Stonewall Jackson’s troops at Chancellorsville. He was captured at Gettysburg after being wounded, temporarily paralyzed and left for dead by his own troops. Confederate Brig. Gen. John B. Gordon took care of Barlow until he recovered, at which point Barlow returned to service in the Union Army. One of Barlow's major accomplishments was to lead his troops in a charge of the "Mule Shoe" at Spotsylvania. They succeeded in capturing 3,000 Confederates, 2 generals, 20 guns and 30 regimental colors. Barlow was called one of the "boy generals" because he kept himself clean-shaven, unlike the predominant practice of sporting a beard or mustache. (One Union officer described him as looking "like a highly independent mounted newsboy.") Although he was frail-looking and pale, he was an intense fighter and strict disciplinarian. After the siege of Petersburg, Barlow's heath failed, although he returned to the army to lead a division at Sayler's Creek and Farmville. He was commissioned a major general on May 25, 1865. After the war, Barlow returned to his law practice, was one of the founders of the American Bar Association, and served as New York State attorney general. (Bio by Scott Rowan)
I can't say I know much about him -- why do you think he should be lowered?
While reading "The Warrior Generals" by Thomas B. Buell (no relation to Don Carlos) I have learned a lot about Barlow. One thing is that Barlow's brigade was not routed at Chancelorsville as it had been detached (a second source for this is wikipedia) to another corps. The second is that only Gordon claims in his memoires that he took care of Barlow at Gettysburg, but according to Buell there is no other source for that.
By the way, Gordon seems to have been an interesting fellow. I would like to do his bio.
"War is the field of chance."
Carl von Clausewitz