Ok from how I made this map the best game possible would probably be with two teams of five or six. The map holds a consistant two-level area with the exception of the outer edges. There is much cover and no holes inside the map to fall from, also the maps gameplay is smooth and frame rate is of no issue.
I can't really tell of this map is good or not. Because the pictures you put it is too small. But I can see is that the aestethics on this map is pretty good to be honest. If you make the pictures larger, I'll can see more details to the map and I comment more about this map. But you've done a good job making this map. - EpICx ReMiX XD
I don't even have too dl this to see there will most likely be framrate problems. You have two lights, which are both shining on 3x3 talls, a peice which already has z fighting. You also said you have added rails. Most likely the ones in the decorative section. Which have lights and z fighting on them. This pretty much spells framerate atrocity. Besides framerate, you're peice usage seems to be quite sparatic. But overall not too shabby for a beginner. Just take into consideration the things I've mentioned above .
Just to let you know I have seen no frame rate issues nor heard anyone else complain about it yet so maybe you SHOULD download it and check it out before you give your opinion. Also at least two cartographers have deemed this worthy of matchmaking material. Also the light issue can be easily fixed if it does occur as an issue.
From your forge world pics it looks like your map is suffering from a dearth of respawn points. Interesting architecture though.