The only way i can see this being played 2v2v2v2 as an exercise in rush. You can simply put gates for blocking the N-S short access routes and the nortern E-w, but for southern E-w you will need to modify the map. Basically get rid of the lowest middle bridge, put tavern to where custom statue is and flood that area.
Base areas are way too small, if you can expand each team of 2's base area until map's corners you can try to put in atleast one expansion goldmine for each team. Put each player's starting position a lil backwards after expanding the base area could also help with the rush issue.
As for another idea on where to put expansions remember there was also 'Old Ironforge' below, if you are willing to expand the map size to either side can make an whole other 'layer' there connected to main map with teleporters representing stairs. Then can populate this 'old ironforge' with expansion mines, creep camps, etc.