Its better to have a broad powerband over a several thousand rpm range than all low or all high. A disadvantage to having all the grunt at 3000 rpm is that you would have to shift sooner and more often when accelerating heavily. If your power is more spread out you have to shift less. I agree that high-strung engines are overrated, though. What's the point of 300 HP when you only have 150 below 8000 RPM?