I really like your experiments with motion blur.
This one is a very beautiful one as well.
The movement has a slight curve in it - I wonder how the
use of a gearhead with 100% vertical movements might have
changed the impression of the image.
Would it be too perfect/technical?
Could it have added something which has something to do with the stability of architecture?
Note really a criticism - more a playing with ideas.
I did attempt to pan straight up and down, but it is difficult with my ball and socket head. It's almost free hand. So you see a slight curve. But to me, it's the expression that makes the image. If it looks good no one cares if you oscillated during your pan. If the image looks ho-hum, then right away people see the technique and not what you were trying to accomplish. A single handle pan head would probably work well. BTW, strong lights are a nuisance in such shots, they tend to create powerful lines of light and overwhelm the image.
Thanks for the comments.