One small issue I have with it is the very heavy shade of green for Central Park. A much lighter shade would probably compete less with the lines (see: Wyman’s approach to National Mall for DC Metro map. Perhaps even lighter than that!).
The type treatment for the borough names feels similarly distracting. Reducing the type size and placing the names so that the lines don’t travel over them may make the map more legible. As it stands now it reminds me too much of a word cloud.
Really nice work!