In War and Peace, subtlety tends to be Tolstoy's technique of choice. We see the way the different members of the aristocracy jockey for slightly higher positions within the ranks of society, the government, or the military. But not much attention is paid to the glaring gulf in early 19th century Russia – the divide between the aristocrats who own the huge estates and the serfs peasants who work them. Several characters make gestures toward making their serfs' lives better, but the general blinkered attitude is not addressed. This is a prominent and telling omission, given that Tolstoy himself was writing at a time when the serfs had finally been declared free.
The characters who care about class differences the most are the ones who suffer least from them.
The book is least progressive in its depiction of the serfs, who are either backward idiots or a threatening mob. Even Platon, the magical, saintly peasant, actually does a disservice to the other serfs: because he is so much less realistic than the other characters, there is nothing particularly humanizing about him that would help make us care about the peasants' treatment.