Ok guys, I am not an architect (but am an architecture fan), but I am thinking of studying architecture and I took the time to consider my design as a regular architect would (I also have a friend that studies urban planning).
So here is my design proposal that I have developed since November:

read more on it at
http://www.geocities.com/davel5957/worldcitycenter/Advantages:
THEMES:
-New York - takes into consideration the setting of NYC
-Monumental - A design to inspire and to symbolize greatness (hence the waterfalls for example)
-Tribute to the original WTC - honors the WTC in a positive light
-Skyscrapers arranged like a mountain to symbolize a mountain of strength, symbolizing NYC after Sept 11th
SKYLINE
-Restores the skyline
-Attempts to add a majestic set of towers to the Lower Manhattan skyline
-Attempts to fit in better with Lower Manhattan's skyline than the original World Trade Center
TOWERS
-6 towers are of different heights to symbolize a mountain to symbolize NYC's strength after 9/11
-One World City Center honors NYC's past, and Two World City Center is supposed to be a toast to NYC's future.
-The 2 main towers have waterfalls that run down them (more likely shielded by glass).
-One World City Center is adorned with a statue holding a beacon that would light up at night to all of New York City
-Both towers go up at least to 1420 ft high in occupied space height and 1,800 ft - 1900 ft in spires
-towers are connected to each other with "bridge towers" that also ensures faster evacuation from the main towers (and can also serve as office space if widened)
GROUND LEVEL
-Adds two great entrances to the main towers
-Establishes a concourse mall that connects all 3 buildings of each side
-establishes a divide between the memorial area and the occupied area
-adds an artificial creek/river that is surrounded by natural greenery and ends in a serene place (in the memorial side)
-adds circles similar to Columbus circle that honor something from 9/11 (ex. the fireman raising the flag statue)
-The plaza in the middle of all of it should be a place for public square useage.
RELATIONSHIP WITH MEMORIAL AND BUILDINGS
-Buildings rise like a strong mountain, but with the waterfall and the silver color of the main towers, serves as a backdrop and honors the original World Trade Center towers
SAFETY FEATURES
Besides the "bridge towers" safety:
-At approximately the 65th - 70th floor, the main towers turn from solid floorplate design to a U design in One World City Center and a donut (with a small hole) in two world city center to give the availability of other evacuation possibilities (well, except falling off :P )
-Since both of the main towers have waterfalls, the pipes used to pump the water could act as a fire hydrant for firemen (hence firemen only have to cross bridge to get to tower and then take available hose and connect to waterfall pump). Either that or a "flood plane" idea involving the pipes as a last resort (yeah, similar to how the fire was put out in the movie: the Towering Inferno)
-Other ideas include arrangement of columns to guard key columns, external columns that could "slice" up just the wings of the airplane, that of which carry most of the jet fuel.