This map is interesting and entertaining. Thank you for taking the time to make the water blue instead of leaving it black like so many mapmakers. It's just far more pleasing to the eye.
The reason I gave 4 (and not 5) stars is that I feel that the map heavily favors players who start in Castello. It is too isolated and easy to defend. The more central parishes, however, exchange hands frequently. Perhaps consider connecting San Giorgio Maggiore to one of the territories in Castello.
The other flaw in this map is that bonus areas award armies disproportionately. For example, Santa Croce Sud and San Polo Est award 3 armies for holding 4 territories. Arsenale actually awards 2 armies for just 2 territories. This creates an imbalance for players who begin in Cannaregio Ovest (3 armies for 7 territories) and several other areas that award 3 armies for 6 territories.