I don't know about Fips but I don't play siege too much so it can take a while before I am able to see how well a new map works, that is why we rely on you to give us feedback, make a thread here or something, or find the creators thread and leave him feedback on how to improve his maps. Remember that map names are messed up so please describe which map it is or post a screenshot of it and please tell us what the problem is and not just 'it sucks'.
http://forum.melee.org/scene-editing/There is always the point though that people need to learn the map to work out what works and what doesn't, so drawing conclusions about balance based on the first few plays does not always do a map justice.
I'm not sure if the size is the problem. On the arabian port map, there seems to be only one way to the flag, which leads to a huge clusterfuck and is almost impossible to win for attackers because of the shorter respawn delay of def.
The arabian port map has an elaborate tunnel system with side routes to each portion of the castle, it is somewhat tricky to properly use though, so I imagine this is an example of a map that people need to learn. I am fairly sure many people won't be using it to its full potential yet, if ever. The final area of the castle has three direct routes. Those three routes still end up at two small staircases which might be too strong as chokepoint, but I can think of a few ways to make it a little easier.