said by xenophon:
The higher bands are still usable to augment lower 'good' bands. Sprint will be able to use iDen 800 to get to hard to reach places but still use upper bands for capacity. That is use 2.5Ghz as first priority, then 1900 if needed, then 800 if needed. So they don't need a huge amount of 7/800 as it will only be needed in hard to reach areas. But the more the better. There's only so much spectrum that exists so all carriers will get as much as they can.
2.5Ghz is not great by itself but is great for augmenting capacity to lower bands.