Well, see the straight roads more of a way to quickly dispatch troops somewhere. This might be to outside the fortress or one of the gatehouses under attack for example. Meerzicht was meant to protect Westdiep and Concetron, but it's also a troop headquarters, meaning if there is trouble anywhere, soldiers would be dispatched from Meerzicht. Also, I am thinking in times of siege that they would be able to throw up barricades by for example using carts and rubble. The straight roads are the most obvious way into the city, but really, you don't want to use them in times of siege. They are meant to draw the enemy in. But as the city has several strong points (two keeps and a castle) where mayor troop concentrations are, it also means that the attacking force can suddenly find defending soldiers at his back.
And I think straight roads are really better for artillery as they need to be able to see their targets from far away. Artillery being archers, ballistas, wizards(they need to see the enemy to kill), etc.
I am not sure if I am going to move the gatehouse of the castle to the south. I think the north is more safe. There it has at least two walls before it. To the south there is only one wall in the harbor! And I want that square in front of the castle to be a bottleneck where defenders can come from all sides if the attackers didn't take their time to really lockdown the city. And locking down this city will be difficult. It can be surrounded of course, but the city of Concetron is to the southeast and if that city still stands the enemy would suddenly find a large army behind itself.
And because the castle hosts the city officials, I also wanted them to have easy access to the road system. Now they can make their grand entry over the larger roads and the big square
Thanks for the feedback, you are still making me think about stuff. And as you noticed I can be influenced
But right now I am leaving the layout as it is, otherwise I will never finish this map. Realism is good and I think I can defend most of my choices, but this is still a fantasy map