An identical tower would look pretty incredible. However, I don't know if we could get away with a set of Twin Towers without being in poor taste.
I think it would look pretty incredible also. I always thought that FCP did sort of look like a WTC tower, just with different cladding (they have the same unwavering skyward box look). Only issue is where would you put the other tower? There isn't really enough room in the existing podium area, as they would presumably need to be offset from eachother (like the WTC towers were, they wern't directly facing eachother). If anything, it would need to go on the north side of Richmond, or directly on the SE corner of Richmond and York. Anything closer would be too close.