Every race has at least one fatal flaw. For the elves, it's basically pride/conservatism (in the original sense of stopping change). Dwarves, greed. Humans, thirst for power. Hobbits, small mindedness. Ents, laziness. Orcs are only flaws basically. They do seem to be able to build machines of war rather well, so they are industrious at least, but only with a strong leader behind them.