The hedge issue was a big one when I played this map. It really pissed us off getting stuck in there.

Pretty cool idea, but i would change your directional lightning and static meshes to dynamic lightning. This diffuse light looks unrealistic with the absence of any shadows.
Also i would reduce the spawntimer a little bit, i tried your map a view times and got rushed on the 2 wave.
Last but not least there are some missplaced pathnotes, e.g. in the hedge.
Anyway, good and optimized (besides difficulty) Map ;-)