Yeah, beings that live for thousands of years can learn a lot. You know what else they can do? Forget. Become jaded. Lose patience. Experience doesn't just pile up and stay forever even if your body stays the same. Tyrande has always been a rash person. She's had endure a lot of shit too. A boyfriend that waited 10,000 years to propose after falling asleep for hundreds or even thousands of years at a time. The whole war of the shifting sands. Velen has led the draenei for 25,000 years, always on the run til they found draenor. Then what happens? The orcs become the servants of their demonic pursuers and expelled them from the home they'd finally found. The night elves and draenei have had far too long to stagnate. The humans are a relatively fresh race still going for their potential reminding the older races of lessons they'd forgotten.
Also, you don't consider Vol'Jin a hero? Not nice man. He's a shadow hunter. Not exactly a guy to bask in the limelight. Doesn't mean he isn't a hero because he doesn't seem to demand fan wank.