I like this map, but looking closely at it, there is a growing list of things that bother me.

The first thing that draws the eyes is the labels. I think they are to bright.
There is no P in the grid system.
Some of the towers are not centered on the wall, particularly in the bottom right corner.
Given the nice compass and the symbol above the town name, I think the map could use a matching border.
I think that the the river lines are too thick. Thinner lines and maybe some shading of the river might be nice.
The contour lines have no scale.
Some of the diagonal lines are jagged, so it could have used a greater resolution.
Being the northern most point of the empire, I would think there should be a northern wall.
It gives me an impression that it was inked yesterday on old paper. If you could somehow fade the city so it looks worn.