Might be interesting to place starting points behind the mountains rather than where you have placed them (ie: top left, bottom right). It could create some more dynamic gameplay, where the way you have placed them curently might be somewhat linear.
WZ is right (gasp! ) the most interesting battles happen over the coveted resource points. See OTA Lava HighGround for example; the most metal is in the center, and the most action happens to take the center.