While I agree with rebuilding the WTC, I feel that people who are concentrated in large quantities or have high profile positions, should be kept in low to the ground buildings. Also, there were too many eggs in one basket there. Heck, it might be time to look at underground structures for such a center, albeit, the view may not be so great.
With the new airport security that's being inplace, hijacks may be a thing of the past (especially by the time the new WTC is built)... and other forms of terrorist attacks would probalby be used... such as a chemical attack, inwhich case you would be glad you were 100 stories above.