Screenshots? I'll look at it soon
For first map this is pretty good and i like it pretty much, maybe cause i failed to do siege map myself but what ever..
Firstly, grass fence doesn't look too nice and the texture you use for ladder, isn't really one of my favorites. In fact i hate it
Construct a good ladder from multiple brushes and you have a lot nicer atmosphere.
Barrel tops have wrong texture, if you look better at the textures you'll see that there's a barrel top texture. I'd also change the color to white, so they don't give any advantage to the other team.
1./2. sshot: Add a ladder to the wall so you can climb up. Makes attacking a lil easier.
3. If this is meant to be a tree, i'd put a tree model here. Search the forum for tree model.
Then maybe you could do a fence next to the walking way on to the building side to give attackers some cover. Make it cool, gates and stuff. For last, iäd add more detail and maybe more light to the upper levels of the building.
Edit: Maybe some plants