RobertTheBruce
King
I don't find the Cothon to be useless... I'll grant you that it's not as impressive as some of the other buildings, but it's a harbor with an extra trade route attached... it all adds up.
Also, I have to wonder if the mods don't just scope this thread out and tweek the save to mess with us just before they put it up
The Cothon is pretty good if you are planning a diplomatic or space race victory.
Pre-astronomy, another trade route will be within your nation and one extra commerce per turn isn't that exciting. Post-astronomy, the trade route can be helpful if you don't have a huge empire. I'm not sure how much the arid conditions will affect city size and trade yield.
If you are planning domination or conquest and already control your continent then its weak but if you have less than a quarter of the cities in the world it can be very useful. It won't help cultural victories unless one of your 3 culture cities is coastal.