Ok, a suggestion: when you make a map, release a test version first. Even if you feel it's done, there might be some things that need to be fixed, so it's good to put out something like mymap_beta1 rather than releasing a map, then fixing it, releasing a new version, and then having all kinds of version conflicts because people have different versions of the map with the same filename.
Onto the review (I'll try to hit everything so you can improve on future maps):
Design. It seems kind of plain - generic 3-room, base-center-base design. Try and come up with something more unique. The whole point of making new maps is to have something new! And whatever your layout is, try to avoid giant, flat, single-texture walls. They look dull and it makes it really easy to see repeated patterns in the textures.
Piles of items... don't do that. It looks dumb to have the hopper, co2, barrel, etc. all merged into one barroppero2. It also makes it so people sometimes pick up the ammo before the hopper and then go pick up a different ammo box leaving somebody else without ammo.
Half-barrels. You can get away with these in dirt/grass maps since they look like they're half-buried, but on a concrete floor? That just doesn't look right. Also, if you do make these these, be sure to align the textures (easiest way is to make a normal barrel, lock the texture [alt-l in bsp] and move the barrel down).
Transparent surfaces. Don't overuse these. They generally look bad. It's OK to use them for a little window here and there, but don't build whole structures out of them. Also using transparent surfaces for major structures removes any stealth strategy. You can't sneak past anybody in plain sight like that.
Lollipop trees. Eww.
Bunkers. Try to give your bunkers some character, rather than just having a solid block with a window in it. Give them a frame, some supports, etc. Take a look at some real paintball bunkers and model after them.
Texture/theme clashing. This is a problem with many paintball maps, so I would recommend getting your inspiration from other mods and/or real life. Take your base entrance, for example. You have a somewhat industrial looking large brick wall, but smack in the middle of it theres a medieval-style metal and wood archway. Put some thought into it and make the layout, textures, details, etc. all work toward one common theme. If you're going to use custom textures, you can really push it far and make your map look exceptionally unique. You have a lot of freedom when making paintball maps. You can do something like a real paintball field or do some kind of crazy medieval theme, or even make a map thats like a real paintball field with a medieval theme having plywood castles an the like.
Lighting. I think you have way too many lights in this map. There are almost no shadows -- everything's just completely lit up.
Welll, that's all for now. Hope this helped.