Increase the space between the wall and the gold mine by 1 square at the expansions under the taverns.
I think it would be a little more natural looking if the corners of trees were arched a little more, and the paths didn't have clean cut ends of trees. And maybe some rocks or other environmental doodads spread around would add some aesthetics; if you use terrain fog and also keep the current global weather dungeon effect, making the terrain fog a similar color, it would create a layered fog effect with light spots and dark spots, because the global weather is not a sheet effect like terrain fog, will also make things outside of vision look more realistic.
Purple and teal, red and orange are very close together, if they are on opposing teams then it will be a very unorthodox game, I personally don't think it is too bad, if that is the style of map you were aiming for; however if it were me I would increase the distance, or add a wall, or move the creeps from the goldmine up to prevent lame early game rushes.
that is a sexy fountain in the middle
obviously a lot of work put in, 3.5/5 =
4/5
I want to try and become a good melee map maker, so if you would like to work together on some melee maps give me a shout