I think I figured out why I wasn't nearly as drained reading about the Civil War as I was while reading "To Conquer Hell."
In to "Conquer Hell" the World War One American division, corps and army commanders really don't see what's going on at the front. The Corps Commanders (commanders of two or more army divisions operating as a single unit) are well behind the lines and are totally clueless about the situation on their front lines in WW1. There's one, a real piece of work named Bulloch who just makes you mad when you read his orders and comments. Mean, Stubborn and Inflexible is no way to command thousands of soldiers, especially if one is far behind the lines in a nice chateau far from the guns.
During the Civil War, corps and division commanders were much closer to the front lines. Much of this was due to the smaller size of Civil War Divisions vs World War One divisions and the lack of effective communication systems outside of couriers. So you had to stay close to your subordinate commanders. As a consequence many of these men were under enemy fire. They also accepted the value of having a general around his men during a tight situation. Many Civil War battles had division commanders and corps commanders under fire and many were wounded or killed. (Winfield Hancock at Gettysburg, Joshua Chamberlain outside of Petersburg, Cleburne at Franklin, Edwin Sumner at Antietam, Joe Hooker at Antietam, Phil Kearney at Chantilly, Reynolds at Gettysburg, Hood at Gettysburg, Longstreet at Wildnerness, the list goes on.)
As a consequence of this I think the generals tended to be more aware of the state of their commands and in most cases lived or died by the consequences of the attacks and defenses they planned and in a great many cases led.
I think there's something that should be learned from this, and George Patton appeared to have it down pretty well, "Lead from the Front." (Patton used a noodle on a plate as a teaching tool for his subordinates to learn this principle. He'd try to push the noodle forward and it wouldn't work, but if you pull the noodle...well then you're in business.)