This looks pretty nice. The biggest issues I can see at the moment are open-ness, size and team differentiation. A Demoman could lob random grenades from just outside his tent to the Hill and possibly further, and Soldiers and Demomen could make it to the other side of the map in one or two explosive jumps. Other than the single sign outside each tent, there is no way to tell which side of the map the player is on. Additional team-coloured props and signs would go a long way.
I suggest that you extend the map into the large structures you have on the edges, moving the spawns inside or behind the structures so that spawn is separated from the main combat area. That way, the size of the map is increased and the main combat area will be fine as is.