Love the design. Really looks great. Perhaps if you increase the shadow cast by the hills (I know people don't lake false shadows, but oh well) they will seem even higher...
Here is my metal layout:

Excuse the poor quality paint JPEG conversion.
Yellow = Metal, White = Geo
(In reviewing it again, I'd probably place two or three more metal patches in the mountain pass, and maybe another in the water)
As you can see, I prefer lower metal distributions which starve the player into occupying key areas. I think the risk here is that the map is a very porc-oriented map. You want to keep the players from sitting back safely in their bases and rush up a Bertha or something. The players need a reason to go outside the comfort zone of their bases.
If you feel there isn't enough metal for more than two players, you could just put a few more metal patches in the general areas I have indicated. The yellow dots are as much "zones of importance" as actual metal patch locations (except for a few at the starting bases which I had to place for the first player to get going, and to allow for 2v2's).
I intentionally kept metal patches off the landing beaches, because I think that they should be kept clear of obstructions, so that they don't block up too quickly, and are kept for the vital purpose of invasions.
Can't wait to try AATA on this map. I hope they have landing craft ready
