I agree, it is an okay read, some parts are pretty good. I like the part where the prince gets wounded in battle, he is fighting and suddenly he is on the ground looking up at how nice the clouds look and wondering what all of the racket is going on around him.
Tolstoy took part in a lot of war. He was, in particular, at the siege of Sebastopol, which was an incredibly bloody business involving constant heavy artillery bombardments. His description of Borodino through the eyes of Pierre Bezukhov, new to war, is extremely compelling. That, most likely, is an accurate description of hus own mental state under those chaotic conditions.
Compare with his own eyewitness account of Sebastopol, the “Sebastopol Sketches”.