Seems like no one took time to comment so far...

The attempt of this map to make a good ctf map feels right. Although how it turned out seems less good. The name may be "walkway", that doesn't mean the flow and gameplay should be exactly like that; straight forward.
I advice you to read the Flow and Layout Guide and try again.

If you are interested in architecture, a good example of it is tempest (Its in sauer). cphills and votivchurch are also, very good examples of architecture, and vampiscratch 1 and 2 (Those are in quadropolis). You should first learn and open your mind watching carefully with outline (press 7 in editmode) all those maps, all the details and buildings, and try to recreate them, or making something similar. I cant help you more than giving you a method to improve your skills.