People seem to like making metal maps, even for OTA. They unfortunately rarely get played, because metal maps tend to lose their playability rather quickly, because they don't encourage anything other than massive slugfests.
I think much more thought is needed for a non-metal map too, because you have to think about metal placement, and the flow of the game based on that metal placement, etc.
And as Over Crude Water taught us, you should stay away from small-span bridges, simply because they get clogged with wreckage and halt the flow of the game.
Not to say your map is bad, but that I think you should perhaps turn your attention to non-metal based maps...
A lot of new people play metal maps because they think that thay look cool...
By the Way, from the screeny id guess that thats no way a 7x7 map.
14 x 14 maybe...