[That is not even close to the problem Gundam is presenting. Have you seen Osaka castle? That is too imperial. It looks like a castle angels would reside in, not demons!!]

Of course I have, but how tall do those actually grow to be? There is no point in selling me on a tower that is not tall enough to serve their purpose. A tower, in a place like this, is an excellent point of presence. Flying into or from a tower that does not, literally, tower over the surrounding area is not nearly as intimidating.