Amazing isn't it? The Midwesterners were backwoodsmen, farmers and tough as nails. The "Westerners" got the job done. The Army of the West kept the Union in the War. Grant, Sherman and many other generals were from Ohio and further west.
"Westerners" had the most to lose. The low cost or even free lands of the West would have gone to larger slave-holding concerns instead of to individuals. The protectionism favored by Republicans protected Westerners much more than the mostly free-trade Southerners as well.
Perhaps that is because a higher percentage of "Eastern Generals" were political appointees? I'm thinking of Ben Butler, and a whole slew of Union BG's & MG's that represented certain key minority groups (Germans, Irish, Poles, etc.) These officers came from the higher population centers on the (north) eastern seaboard. A lot of them got volunteer appointments from their respective state governors. Very few were worth a d@mn.
You'd be suprised what you can accomplish when you give a group of pissed off millers and lumberjacks rifles.