I've been thinking about the reasons that War and Peace is impressing me so much while Resurrection left me flat. The main idea I've come up with is the different motivation Tolstoy must have had while writing. War and Peace is filled with astute and detailed observations of his characters that bring them to life, while the characters in Resurrection feel as if they have been manipulated into becoming evidence to justify Tolstoy's point of view concerning prison reform. In one case Tolstoy was an observer of humanity. In the other he was trying to change humanity.
General Kutuzov is a good example of the way Tolstoy used his observance of human characteristics to make his portrayal of this, real general into a full bodied character. Here's a paragraph that demonstrates this:
The Russians did not seek out the best position but, on the contrary, during the retreat passed many positions better than Borodino. They did not stop at any one of these positions because Kutuzov did not wish to occupy a position he had not himself chosen, because the popular demand for a battle had not yet expressed itself strongly enough, and because Miloradovich had not yet arrived with the militia, and for many other reasons. The fact is that other positions they had passed were stronger, and that the position at Borodino (the one where the battle was fought), far from being strong, was no more a position than any other spot one might find in the Russian Empire by sticking a pin into the map at hazard.
In this paragraph Tolstoy shows how Kutuzov thought of all aspects, including political strength, before making his decision. Tolstoy didn't pass judgment on this process he simply reported it. Aspects of it might have been true, but it is far more likely to be a scene created in the mind of an great writer of fiction.